Example recommendable controller implementation

beers_controller.rb

class BeersController < ApplicationController
  def like
    @beer = Beer.find(params[:id])

    respond_to do |format|
      if current_user.like @beer
        # respond to HTML with a redirect, render ajax js, etc.
      else
        # flash[:error], if you wish
      end
    end
  end

  def dislike
    @beer = Beer.find(params[:id])

    respond_to do |format|
      if current_user.dislike @beer
        # respond to HTML with a redirect, render ajax js, etc.
      else
        # flash[:error], if you wish
      end
    end
  end

  # etc.
end