gistfile1.rb

module Models
  module Connections
    extend ActiveSupport::Concern

    included do
      class_attribute :using_database, :_database_config
    end


    module ClassMethods
      def database_config=(config)
        _database_config = config.to_hash if config.respond_to(:to_hash)
      end

      def using(dbname, &block)
        return unless block_given?

        establish_connection(_database_config[dbname])
        self.using_database = dbname
        yield(self)
        self.using_database = Rails.env
        establish_connection(Rails.env)
      end
    end
  end
end