me_gusta.rb

class ActiveRecord::Base
  class << self
    def use_ilike_in_conditions_for_postgres(*conditions)
      conditions = conditions.dup
      
      @postgres_database ||= connection && 
                             connection.class.to_s.include?("PostgreSQLAdapter")
                             
      if @postgres_database && has_like_operator?(conditions)
        conditions.each { |condition| replace_like_operator(condition) }
      end
      
      super_merge_conditions(*conditions)
    end
    
    private
    
      def replace_like_operator(condition)
        if condition.is_a?(Array)
          condition.each { |c| replace_like_operator(c) }
        elsif condition.is_a?(String)
          condition.gsub!(/ like /i, " ilike ") if condition.is_a?(String)          
        end
      end
      
      def has_like_operator?(conditions)
        conditions.flatten.join =~ / like /i
      end
  
    alias_method :super_merge_conditions, :merge_conditions
    alias_method :merge_conditions, :use_ilike_in_conditions_for_postgres
  end
end