class Bundler::Dsl

def self.deprecate(name, replacement = nil)
  define_method(name) do |*|
    message = "'#{name}' has been removed from the Gemfile DSL, "
    if replacement
      message << "and has been replaced with '#{replacement}'."
    else
      message << "and is no longer supported."
    end
    message << "\nSee the README for more information on upgrading from Bundler 0.8."
    raise DeprecatedError, message
  end
end