Issue with ember-cli-rails and puma-dev

Just getting started with a rails api and ember frontend. I'm using ember-cli-rails and puma-dev. I'm getting an error when visiting the localhost at .test. I'm not sure what is causing it, or if it's due to both the front and back end bring set to "/".

Any point in the right direction would be appreciated!

NoMethodError undefined method `has_key?' for nil:NilClass Extracted source (around line #19):

  def action_encoding_template(action) # :nodoc:
    *if @_parameter_encodings.has_key?(action.to_s)*
      @_parameter_encodings[action.to_s]
    end
  end

https://github.com/wjacobs71086/keenmind