RoRで作ったアプリをherokuにデプロイ

$ git push heroku master

したら以下のようなエラーが

remote:        An error occurred while installing sqlite3 (1.3.13), and Bundler cannot
remote:        continue
remote:        Make sure that `gem install sqlite3 -v '1.3.13'` succeeds before bundling.
remote:        
remote:        In Gemfile:
remote:          sqlite3
remote:
remote:  !
remote:  !     Failed to install gems via Bundler.
remote:  !     Detected sqlite3 gem which is not supported on Heroku:
remote:  !     https://devcenter.heroku.com/articles/sqlite3
remote:  !
remote:  !     Push rejected, failed to compile Ruby app.
remote:
remote:  !     Push failed
remote: Verifying deploy...
remote:
remote: ! Push rejected to glacial-tor-45483.
remote:
To https://git.heroku.com/glacial-tor-45483.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/glacial-tor-45483.git'

gemfileの

gem 'sqlite3'

をコメントアウトして

gem 'sqlite3', groups: %w(test development), require: false
gem 'pg', groups: %w(production), require: false

を挿入。

その後

bundle install

としたら、postgresqlがインストールされていないと怒らえる。

An error occurred while installing pg (1.1.3), and Bundler cannot continue.
Make sure that `gem install pg -v '1.1.3' --source 'https://rubygems.org/'` succeeds before bundling.

postgresqlをインストール