title: Heroku Application Error (Ruby 2.2.2)
body: <p>I have a Rails app and I try to push it to Heroku. After I pushed it to Heroku, I get Application Error message.</p>
  
  <p>When I run <code>heroku logs -n 300</code>, I get <a href="https://gist.github.com/anonymous/56a2871b4de3576e2417" rel="nofollow">this</a> (sorry for pasting the logs in Gist. StackOverflow not allowing me to post >30K characters question).</p>
  
  <p>This is my Gemfile:</p>
  
  <pre><code>source 'https://rubygems.org'
  
  
  # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
  gem 'rails', '4.2.1'
  
  # Use SCSS for stylesheets
  gem 'sass-rails', '~&gt; 5.0'
  
  # Use Uglifier as compressor for JavaScript assets
  gem 'uglifier', '&gt;= 1.3.0'
  
  # Use CoffeeScript for .coffee assets and views
  gem 'coffee-rails', '~&gt; 4.1.0'
  
  # Use jquery as the JavaScript library
  gem 'jquery-rails'
  
  # Twitter Bootstrap
  gem 'bootstrap-sass', '3.2.0.0'
  
  # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
  gem 'jbuilder', '~&gt; 2.0'
  # bundle exec rake doc:rails generates the API under doc/api.
  gem 'sdoc', '~&gt; 0.4.0', group: :doc
  
  # Devise for user auth
  gem 'devise'
  
  # CanCanCan for user roles
  gem 'cancancan', '~&gt; 1.10'
  
  # Gravatar
  gem 'gravatar_image_tag'
  
  # Font Awesome
  gem 'font-awesome-sass'
  
  group :development, :test do
    # Use sqlite3 as the database for Active Record
    gem 'sqlite3'
  
    # Call 'byebug' anywhere in the code to stop execution and get a debugger console
    gem 'byebug'
  
    # Access an IRB console on exception pages or by using &lt;%= console %&gt; in views
    gem 'web-console', '~&gt; 2.0'
  
    # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
    gem 'spring'
  end
  
  group :production do
    gem 'pg',             '0.17.1'
    gem 'rails_12factor', '0.0.2'
  end
  
  ruby "2.2.2"
  </code></pre>
  
  <p>I thought that the error is because I'm not running <code>rake db:migrate</code> on Heroku. But, after I run <code>heroku run rake db:migrate</code>, the error is still same.</p>
  
  <p>What should I do?</p>
  
  <p>Note: This app runs well on my localhost.</p>