Redmineの導入がうまくいきません、、、助けてください！！ちゃんと勉強するので

Question

Redmineの導入時間がかかっており大変苦戦しております。
ちなみにサーバーのストレージ不足でBitnamiはダウンロードできません、、、、泣（本当はストレージ増やしてほしいんですけど・・・）

躓いてるところは二つで
ひとつはRubyをインストールした後Bundleコマンドが使用できません。
最後に以下のようなエラーがでます。
参考手順サイト
http://redmine.jp/guide/RedmineInstall/
4のところからできません

Don't run Bundler as root. Bundler can ask for sudo if it is needed, and
installing your bundle as root will break this application for all non-root
users on this machine.
The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x64-mingw32, x86-mswin32, java. To add those platforms to the bundle, run `bundle lock --add-platform x86-mingw32 x64-mingw32 x86-mswin32 java`.
The dependency activerecord-jdbc-adapter (~> 1.3.2) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for java. To add those platforms to the bundle, run `bundle lock --add-platform java`.
The dependency activerecord-jdbcpostgresql-adapter (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for java. To add those platforms to the bundle, run `bundle lock --add-platform java`.
Fetching gem metadata from https://rubygems.org/..........
Fetching version metadata from https://rubygems.org/..
Fetching dependency metadata from https://rubygems.org/.
Resolving dependencies...
Using rake 12.0.0
Using i18n 0.8.1
Using json 1.8.6
Using minitest 5.10.1
Using thread_safe 0.3.6
Using builder 3.2.3
Using erubis 2.7.0
Using mini_portile2 2.1.0
Using rack 1.6.5
Using mime-types-data 3.2016.0521
Using arel 6.0.4
Using public_suffix 2.0.5
Using bundler 1.14.6
Using coderay 1.1.1
Using concurrent-ruby 1.0.5
Using htmlentities 4.3.4
Using thor 0.19.4
Using mimemagic 0.3.2
Using net-ldap 0.12.1
Installing pg 0.18.4 with native extensions
Using ruby-openid 2.3.0
Using rbpdf-font 1.19.1
Using redcarpet 3.3.4
Using request_store 1.0.5
Installing rmagick 2.16.0 with native extensions
Using tzinfo 1.2.3
Using nokogiri 1.7.1
Using rack-test 0.6.3
Using mime-types 3.1
Using addressable 2.5.1
Using sprockets 3.7.1
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

/root/.rbenv/versions/2.2.3/bin/ruby -r ./siteconf20170331-9474-1v7pivf.rb
extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=/root/.rbenv/versions/2.2.3/bin/$(RUBY_BASE_NAME)
        --with-pg
        --without-pg
        --enable-windows-cross
        --disable-windows-cross
        --with-pg-config
        --without-pg-config
        --with-pg_config
        --without-pg_config
        --with-pg-dir
        --without-pg-dir
        --with-pg-include
        --without-pg-include=${pg-dir}/include
        --with-pg-lib
        --without-pg-lib=${pg-dir}/lib

extconf failed, exit code 1

Gem files will remain installed in
/root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/pg-0.18.4 for inspection.
Results logged to
/root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/extensions/x86_64-linux/2.2.0-static/pg-0.18.4/gem_make.out
**
An error occurred while installing pg (0.18.4), and Bundler cannot
continue.
Make sure that `gem install pg -v '0.18.4'` succeeds before bundling.**

もう一つはappcheのDocumentRootがうまくつながらないということです。
こっちの手順はこのサイトを参考にしています。
http://blog.redmine.jp/articles/2_3/installation_centos/

#
# Note that from this point forward you must specifically allow
# particular features to be enabled - so if something's not working as
# you might expect, make sure that you have specifically enabled it
# below.
#

#
# DocumentRoot: The directory out of which you will serve your
# documents. By default, all requests are taken from this directory, but
# symbolic links and aliases may be used to point to other locations.
#
DocumentRoot "/opt/redmine-3.3.2/public"

たぶんパスはあってるですがIPをブラウザに入力してもRedmineの画面ではなくAppacheのTomcatの設定画面のような画面になります。

Answer 1

Redmineはやったことがないので、間違えていたらすみません。

1つめの問題については、以下のサイトが参考になると思います。
gem install pgしてNo pg_configとなる対処法

Ubuntuでは、以下のコマンドで良いそうです（わたしはこんなコマンド見たことありませんが...）。

$ sudo aptitude install libpq-dev

追記

apt-getでも良いみたいです。

$ sudo apt-get install libpq-dev

必要ライブラリがありません事案の救世主apt-file