You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: config_context.rb
    path of file: ./repos/middleman/middleman-core/lib/middleman-core
    
    the code of the file until where you have to start completion: require 'rack/mime'
require 'middleman-core/callback_manager'

module Middleman
  class ConfigContext
    extend Forwar
    
    def include_environment(name)
      path = File.dirname(__FILE__)
      other_config = File.join(path, name.to_s)

      return unless File.exist? other_config

      instance_eval File.read(other_config), other_config, 1
    end