title: When I rake db:migrate, an ArgumentError appears
body: <p>I want to start my project over from a remote commit so, after downloading the zipfile and puting back all of the .gitignore files, I recieve this error when I try to rake db:migrate. </p>
  
  <pre><code>ArgumentError: Missing required arguments: aws_access_key_id, aws_secret_access_key
  2.1.5/gems/fog-core-1.25.0/lib/fog/core/service.rb:234:in `validate_options'
  2.1.5/gems/fog-core-1.25.0/lib/fog/core/service.rb:258:in `handle_settings'
  /s/ruby-2.1.5/gems/fog-core-1.25.0/lib/fog/core/service.rb:98:in `new'
  /gems/fog-core-1.25.0/lib/fog/storage.rb:25:in `new'
  gems/carrierwave-carrierwave/uploader/configuration.rb:83:in `eager_load_fog'
  //.rvm/gems/ruby-2.1.5/gems/carrierwave-0.10.0/lib/carrierwave/uploader/configuration.rb:96:in     `fog_credentials='
  /bloccit/config/initializers/fog.rb:2:in `block in &lt;top (required)&gt;'
  e/.rvm/gems/ruby-2.1.5/gems/carrierwave-0.10.0/lib/carrierwave/uploader/configuration.rb:118:in `configure'
  </code></pre>
  
  <p>So, I know there's something wrong with my fog.rb file, but how do I fix it? And where is a good place to put the values for AWS codes?</p>
  
  <p>My fog.rb</p>
  
  <pre><code>CarrierWave.configure do |config|
      config.fog_credentials = {
      provider:               'AWS',
      aws_access_key_id:      ENV['AWS_ACCESS_KEY_ID'],
      aws_secret_access_key:  ENV['AWS_SECRET_ACCESS_KEY']
  }
  config.fog_directory   = ENV['AWS_BUCKET']
  config.fog_public      = true
  end
  </code></pre>