Djangoで予約可能人数の上限をあげたい。

###解決したいこと
現在、自作アプリに予約システムを実装しようとしています。こちらのサイトからクローンでアプリにひとまず実装でき、これから自分用にカスタマイズしようといったところです。

アプリのイメージは以下のようなものです。
⑴好きなカテゴリーを選択⑵オーガナイザーを選択⑶日時を決めて予約といった流れで、好きなカテゴリーについて話せる場を作れればいいなと思い、開発を進めています。

現状、クローンで実装したこともあり1つの「カテゴリー・オーガナイザー・日時」の枠で1人まで予約するところまでは問題なく進みました。で、カスタマイズをしようという段階なのですが、一つの「カテゴリー・オーガナイザー・日時」に対して予約できる人数を５人にしたいです。

###関連コード

python
1models.py
2
3class Category(models.Model):
4    name = models.CharField('Category', max_length=255)
5
6    def __str__(self):
7        return self.name
8
9
10class Staff(models.Model):
11    name = models.CharField('Name', max_length=50)
12    user = models.ForeignKey(
13        settings.AUTH_USER_MODEL, verbose_name='ログインユーザー', on_delete=models.CASCADE
14    )
15    category = models.ForeignKey(Category, verbose_name='カテゴリー', on_delete=models.CASCADE)
16
17    class Meta:
18        constraints = [
19            models.UniqueConstraint(fields=['user', 'category'], name='unique_staff'),
20        ]
21
22    def __str__(self):
23        return f'{self.category.name} - {self.name}'
24
25
26class Schedule(models.Model):
27    start = models.DateTimeField('Start')
28    end = models.DateTimeField('End')
29    name = models.CharField('Name', max_length=255)
30    staff = models.ForeignKey('Staff', verbose_name='スタッフ', on_delete=models.CASCADE)
31
32    def __str__(self):
33        start = timezone.localtime(self.start).strftime('%Y/%m/%d %H:%M:%S')
34        end = timezone.localtime(self.end).strftime('%Y/%m/%d %H:%M:%S')
35        return f'{self.name} {start} ~ {end} {self.staff}'
36

python
1
2#views.py
3
4from django.shortcuts import render
5
6# Create your views here.
7
8User = get_user_model()
9
10
11class OnlyStaffMixin(UserPassesTestMixin):
12    raise_exception = True
13
14    def test_func(self):
15        staff = get_object_or_404(Staff, pk=self.kwargs['pk'])
16        return staff.user == self.request.user or self.request.user.is_superuser
17
18
19class OnlyScheduleMixin(UserPassesTestMixin):
20    raise_exception = True
21
22    def test_func(self):
23        schedule = get_object_or_404(Schedule, pk=self.kwargs['pk'])
24        return schedule.staff.user == self.request.user or self.request.user.is_superuser
25
26
27class OnlyUserMixin(UserPassesTestMixin):
28    raise_exception = True
29
30    def test_func(self):
31        return self.kwargs['pk'] == self.request.user.pk or self.request.user.is_superuser
32
33
34class CategoryList(generic.ListView):
35    model = Category
36    ordering = 'name'
37
38
39class StaffList(generic.ListView):
40    model = Staff
41    ordering = 'name'
42
43    def get_context_data(self, **kwargs):
44        context = super().get_context_data(**kwargs)
45        context['category'] = self.category
46        return context
47
48    def get_queryset(self):
49        category = self.category = get_object_or_404(Category, pk=self.kwargs['pk'])
50        queryset = super().get_queryset().filter(category=category)
51        return queryset
52
53
54class StaffCalendar(generic.TemplateView):
55    template_name = 'book/calendar.html'
56
57    def get_context_data(self, **kwargs):
58        context = super().get_context_data(**kwargs)
59        staff = get_object_or_404(Staff, pk=self.kwargs['pk'])
60        today = datetime.date.today()
61
62        # どの日を基準にカレンダーを表示するかの処理。
63        # 年月日の指定があればそれを、なければ今日からの表示。
64        year = self.kwargs.get('year')
65        month = self.kwargs.get('month')
66        day = self.kwargs.get('day')
67        if year and month and day:
68            base_date = datetime.date(year=year, month=month, day=day)
69        else:
70            base_date = today
71
72        # カレンダーは1週間分表示するので、基準日から1週間の日付を作成しておく
73        days = [base_date + datetime.timedelta(days=day) for day in range(7)]
74        start_day = days[0]
75        end_day = days[-1]
76
77        # 9時から17時まで1時間刻み、1週間分の、値がTrueなカレンダーを作る
78        calendar = {}
79        for hour in range(9, 18):
80            row = {}
81            for day in days:
82                row[day] = True
83            calendar[hour] = row
84
85        # カレンダー表示する最初と最後の日時の間にある予約を取得する
86        start_time = datetime.datetime.combine(start_day, datetime.time(hour=9, minute=0, second=0))
87        end_time = datetime.datetime.combine(end_day, datetime.time(hour=17, minute=0, second=0))
88        for schedule in Schedule.objects.filter(staff=staff).exclude(Q(start__gt=end_time) | Q(end__lt=start_time)):
89            local_dt = timezone.localtime(schedule.start)
90            booking_date = local_dt.date()
91            booking_hour = local_dt.hour
92            if booking_hour in calendar and booking_date in calendar[booking_hour]:
93                calendar[booking_hour][booking_date] = False
94
95        context['staff'] = staff
96        context['calendar'] = calendar
97        context['days'] = days
98        context['start_day'] = start_day
99        context['end_day'] = end_day
100        context['before'] = days[0] - datetime.timedelta(days=7)
101        context['next'] = days[-1] + datetime.timedelta(days=1)
102        context['today'] = today
103        context['public_holidays'] = settings.PUBLIC_HOLIDAYS
104        return context
105
106
107class Booking(generic.CreateView):
108    model = Schedule
109    fields = ('name',)
110    template_name = 'book/booking.html'
111
112    def get_context_data(self, **kwargs):
113        context = super().get_context_data(**kwargs)
114        context['staff'] = get_object_or_404(Staff, pk=self.kwargs['pk'])
115        return context
116
117    def form_valid(self, form):
118        staff = get_object_or_404(Staff, pk=self.kwargs['pk'])
119        year = self.kwargs.get('year')
120        month = self.kwargs.get('month')
121        day = self.kwargs.get('day')
122        hour = self.kwargs.get('hour')
123        start = datetime.datetime(year=year, month=month, day=day, hour=hour)
124        end = datetime.datetime(year=year, month=month, day=day, hour=hour + 1)
125        if Schedule.objects.filter(staff=staff, start=start).exists():
126            messages.error(self.request, 'Sorry, No empty')
127        else:
128            schedule = form.save(commit=False)
129            schedule.staff = staff
130            schedule.start = start
131            schedule.end = end
132            schedule.save()
133        return redirect('book:calendar', pk=staff.pk, year=year, month=month, day=day)
134
135
136class MyPage(LoginRequiredMixin, generic.TemplateView):
137    template_name = 'book/my_page.html'
138
139    def get_context_data(self, **kwargs):
140        context = super().get_context_data(**kwargs)
141        context['staff_list'] = Staff.objects.filter(user=self.request.user).order_by('name')
142        context['schedule_list'] = Schedule.objects.filter(staff__user=self.request.user, start__gte=timezone.now()).order_by('name')
143        return context
144
145
146class MyPageWithPk(OnlyUserMixin, generic.TemplateView):
147    template_name = 'book/my_page.html'
148
149    def get_context_data(self, **kwargs):
150        context = super().get_context_data(**kwargs)
151        context['user'] = get_object_or_404(User, pk=self.kwargs['pk'])
152        context['staff_list'] = Staff.objects.filter(user__pk=self.kwargs['pk']).order_by('name')
153        context['schedule_list'] = Schedule.objects.filter(staff__user__pk=self.kwargs['pk'], start__gte=timezone.now()).order_by('name')
154        return context
155
156
157class MyPageCalendar(OnlyStaffMixin, StaffCalendar):
158    template_name = 'book/my_page_calendar.html'
159
160
161class MyPageDayDetail(OnlyStaffMixin, generic.TemplateView):
162    template_name = 'book/my_page_day_detail.html'
163
164    def get_context_data(self, **kwargs):
165        context = super().get_context_data(**kwargs)
166        pk = self.kwargs['pk']
167        staff = get_object_or_404(Staff, pk=pk)
168        year = self.kwargs.get('year')
169        month = self.kwargs.get('month')
170        day = self.kwargs.get('day')
171        date = datetime.date(year=year, month=month, day=day)
172
173        # 9時から17時まで1時間刻みのカレンダーを作る
174        calendar = {}
175        for hour in range(9, 18):
176            calendar[hour] = []
177
178        # カレンダー表示する最初と最後の日時の間にある予約を取得する
179        start_time = datetime.datetime.combine(date, datetime.time(hour=9, minute=0, second=0))
180        end_time = datetime.datetime.combine(date, datetime.time(hour=17, minute=0, second=0))
181        for schedule in Schedule.objects.filter(staff=staff).exclude(Q(start__gt=end_time) | Q(end__lt=start_time)):
182            local_dt = timezone.localtime(schedule.start)
183            booking_date = local_dt.date()
184            booking_hour = local_dt.hour
185            if booking_hour in calendar:
186                calendar[booking_hour].append(schedule)
187
188        context['calendar'] = calendar
189        context['staff'] = staff
190        return context
191
192
193class MyPageSchedule(OnlyScheduleMixin, generic.UpdateView):
194    model = Schedule
195    fields = ('start', 'end', 'name')
196    success_url = reverse_lazy('book:my_page')
197
198
199class MyPageScheduleDelete(OnlyScheduleMixin, generic.DeleteView):
200    model = Schedule
201    success_url = reverse_lazy('book:my_page')
202
203
204@require_POST
205def my_page_holiday_add(request, pk, year, month, day, hour):
206    staff = get_object_or_404(Staff, pk=pk)
207    if staff.user == request.user or request.user.is_superuser:
208        start = datetime.datetime(year=year, month=month, day=day, hour=hour)
209        end = datetime.datetime(year=year, month=month, day=day, hour=hour + 1)
210        Schedule.objects.create(staff=staff, start=start, end=end, name='休暇(システムによる追加)')
211        return redirect('book:my_page_day_detail', pk=pk, year=year, month=month, day=day)
212
213    raise PermissionDenied
214