HerokuのApplication errorを解決したい

Web技術速習テキスト実践編という本を勉強中なのですが、
Herokuにアップロードする時に
ed9869ce76dc4178d0d39a5d4d0fdabc.png

上記のようなエラーが出ており困っています。
heroku logs --tail
を入力した所、

発生している問題・エラーメッセージ

2020-08-06T13:32:58.657861+00:00 heroku[web.1]: Process exited with status 1
2020-08-06T13:32:58.700052+00:00 heroku[web.1]: State changed from starting to crashed
2020-08-06T13:36:00.540498+00:00 app[api]: Starting process with command `rails c` by aaaaaaa@yahoo.co.jp
2020-08-06T13:36:03.975371+00:00 heroku[run.7789]: State changed from starting to up
2020-08-06T13:36:04.225696+00:00 heroku[run.7789]: Awaiting client
2020-08-06T13:36:04.264319+00:00 heroku[run.7789]: Starting process with command `rails c`
2020-08-06T13:36:08.848833+00:00 heroku[run.7789]: Process exited with status 127
2020-08-06T13:36:08.895306+00:00 heroku[run.7789]: State changed from up to complete
～中略～
2020-08-06T13:55:35.722874+00:00 heroku[web.1]: State changed from crashed to starting
2020-08-06T13:55:38.340494+00:00 heroku[web.1]: Starting process with command `npm start`
2020-08-06T13:55:40.964278+00:00 app[web.1]: npm ERR! missing script: start
2020-08-06T13:55:40.978144+00:00 app[web.1]:
2020-08-06T13:55:40.978843+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2020-08-06T13:55:40.979183+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2020-08-06T13_55_40_973Z-debug.log
2020-08-06T13:55:41.051204+00:00 heroku[web.1]: Process exited with status 1
2020-08-06T13:55:41.107856+00:00 heroku[web.1]: State changed from starting to crashed
2020-08-06T13:55:41.110019+00:00 heroku[web.1]: State changed from crashed to starting
2020-08-06T13:55:43.076139+00:00 heroku[web.1]: Starting process with command `npm start`
2020-08-06T13:55:45.246552+00:00 app[web.1]: npm ERR! missing script: start
2020-08-06T13:55:45.254766+00:00 app[web.1]:
2020-08-06T13:55:45.255070+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2020-08-06T13:55:45.255224+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2020-08-06T13_55_45_247Z-debug.log
2020-08-06T13:55:45.302387+00:00 heroku[web.1]: Process exited with status 1
2020-08-06T13:55:45.342516+00:00 heroku[web.1]: State changed from starting to crashed
2020-08-06T13:55:53.049318+00:00 app[api]: Starting process with command `rails c` by user aaaaaaa@yahoo.co.jp
2020-08-06T13:55:56.340010+00:00 heroku[run.7455]: State changed from starting to up
2020-08-06T13:55:56.608107+00:00 heroku[run.7455]: Awaiting client
2020-08-06T13:55:56.653174+00:00 heroku[run.7455]: Starting process with command `rails c`
2020-08-06T13:56:01.232874+00:00 heroku[run.7455]: Process exited with status 127
2020-08-06T13:56:01.276098+00:00 heroku[run.7455]: State changed from up to complete
2020-08-06T13:57:24.096270+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=peaceful-ravine-19598.herokuapp.com request_id=27e02557-6bf9-4b87-b021-502c2d49b128 fwd="217.178.19.79" dyno= connect= service= status=503 bytes= protocol=https
2020-08-06T13:57:24.712311+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=peaceful-ravine-19598.herokuapp.com request_id=76327658-ae2b-451d-93c9-17b412e6b044 fwd="217.178.19.79" dyno= connect= service= status=503 bytes= protocol=https
2020-08-06T14:21:13.068061+00:00 heroku[web.1]: State changed from crashed to starting
2020-08-06T14:21:15.163156+00:00 heroku[web.1]: Starting process with command `npm start`
2020-08-06T14:21:17.534995+00:00 app[web.1]: npm ERR! missing script: start
2020-08-06T14:21:17.543270+00:00 app[web.1]:
2020-08-06T14:21:17.543528+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2020-08-06T14:21:17.543605+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2020-08-06T14_21_17_536Z-debug.log
2020-08-06T14:21:17.591573+00:00 heroku[web.1]: Process exited with status 1
2020-08-06T14:21:17.630214+00:00 heroku[web.1]: State changed from starting to crashed
2020-08-06T14:23:29.571843+00:00 app[api]: Starting process with command `bundle install` by user aaaaaaaa@yahoo.co.jp
2020-08-06T14:23:32.965180+00:00 heroku[run.9355]: State changed from starting to up
2020-08-06T14:23:33.384197+00:00 heroku[run.9355]: Awaiting client
2020-08-06T14:23:33.416110+00:00 heroku[run.9355]: Starting process with command `bundle install`
2020-08-06T14:23:38.291480+00:00 heroku[run.9355]: Process exited with status 127
2020-08-06T14:23:38.342594+00:00 heroku[run.9355]: State changed from up to complete
2020-08-06T14:24:09.512020+00:00 app[api]: Starting process with command `gem install bundler` by user aaaaaaaa@yahoo.co.jp
2020-08-06T14:24:13.369267+00:00 heroku[run.9676]: State changed from starting to up
2020-08-06T14:24:13.702399+00:00 heroku[run.9676]: Awaiting client
2020-08-06T14:24:13.738465+00:00 heroku[run.9676]: Starting process with command `gem install bundler`
2020-08-06T14:24:19.901658+00:00 heroku[run.9676]: Process exited with status 1
2020-08-06T14:24:19.948336+00:00 heroku[run.9676]: State changed from up to complete
2020-08-06T14:24:36.689980+00:00 app[api]: Starting process with command `ll` by user aaaaaaa@yahoo.co.jp
2020-08-06T14:24:40.116445+00:00 heroku[run.1231]: State changed from starting to up
2020-08-06T14:24:40.283029+00:00 heroku[run.1231]: Awaiting client
2020-08-06T14:24:40.312843+00:00 heroku[run.1231]: Starting process with command `ll`
2020-08-06T14:24:44.967095+00:00 heroku[run.1231]: Process exited with status 127
2020-08-06T14:24:45.012380+00:00 heroku[run.1231]: State changed from up to complete
2020-08-06T14:25:14.031192+00:00 app[api]: Starting process with command `ls -l` by user aaaaaaaa@yahoo.co.jp
2020-08-06T14:25:17.928246+00:00 heroku[run.7120]: State changed from starting to up
2020-08-06T14:25:18.062660+00:00 heroku[run.7120]: Awaiting client
2020-08-06T14:25:18.092007+00:00 heroku[run.7120]: Starting process with command `ls -l`
2020-08-06T14:25:22.520124+00:00 heroku[run.7120]: Process exited with status 0
2020-08-06T14:25:22.573042+00:00 heroku[run.7120]: State changed from up to complete
2020-08-06T14:27:52.508266+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=peaceful-ravine-19598.herokuapp.com request_id=f0728855-d4b6-4b36-af1e-ba8738a3ad0c fwd="217.178.19.79" dyno= connect= service= status=503 bytes= protocol=https
2020-08-06T14:27:54.162704+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=peaceful-ravine-19598.herokuapp.com request_id=27690eb5-50dd-4e11-bae0-4733cd20d4a1 fwd="217.178.19.79" dyno= connect= service= status=503 bytes= protocol=https
2020-08-06T14:28:51.254629+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=peaceful-ravine-19598.herokuapp.com request_id=ed293cf5-7bda-4c4c-a350-23a2a98f88f7 fwd="217.178.19.79" dyno= connect= service= status=503 bytes= protocol=https
2020-08-06T14:28:51.813099+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=peaceful-ravine-19598.herokuapp.com request_id=974795db-2e89-4cff-bade-2b6adc1361e1 fwd="217.178.19.79" dyno= connect= service= status=503 bytes= protocol=https
2020-08-06T14:29:24.663619+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=peaceful-ravine-19598.herokuapp.com request_id=acc460f1-ac8a-4287-b03a-10fefcad77f2 fwd="217.178.19.79" dyno= connect= service= status=503 bytes= protocol=https
2020-08-06T14:29:24.943064+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=peaceful-ravine-19598.herokuapp.com request_id=5c079bc0-4976-483a-9851-7d20365a8425 fwd="217.178.19.79" dyno= connect= service= status=503 bytes= protocol=https

となりました。
更に
heroku run rails console
してエラーメッセージを見た所、
Running rails console on ⬢ peaceful-ravine-19598... up, run.5181 (Free)
bash: rails: command not found
となりました。

bash: rails: command not found
を解決すれば出来そうなのですが解決方法がわかりません。
よろしくお願いします。