method_source needs to be a hard dependency on railties

Gemfile

@@ -60,7 +60,6 @@ instance_eval File.read local_gemfile if File.exist? local_gemfile
 group :test do
   # FIX: Our test suite isn't ready to run in random order yet
   gem 'minitest', '< 5.3.4'
-  gem 'method_source'
 
   platforms :mri_19 do
     gem 'ruby-prof', '~> 0.11.2'

Gemfile.lock

@@ -87,6 +87,7 @@ PATH
     railties (5.0.0.alpha)
       actionpack (= 5.0.0.alpha)
       activesupport (= 5.0.0.alpha)
+      method_source
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
 
@@ -261,7 +262,6 @@ DEPENDENCIES
   json
   kindlerb (= 0.1.1)
   mail!
-  method_source
   minitest (< 5.3.4)
   mocha (~> 0.14)
   mysql (>= 2.9.0)

railties/lib/rails/generators/rails/app/templates/Gemfile

@@ -36,10 +36,6 @@ group :development, :test do
   # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
   gem 'spring'
 <% end  -%>
-
-  # Adds `Method#source` and `Method#comment` to get the source code of a
-  # method from the console
-  gem 'method_source'
 <% end  -%>
 end
 <% if  RUBY_PLATFORM.match(/bccwin|cygwin|emx|mingw|mswin|wince|java/) -%>

railties/railties.gemspec

@@ -28,6 +28,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency 'rake', '>= 0.8.7'
   s.add_dependency 'thor', '>= 0.18.1', '< 2.0'
+  s.add_dependency 'method_source'
 
   s.add_development_dependency 'actionview', version
 end

railties/test/generators/app_generator_test.rb

@@ -443,13 +443,6 @@ class AppGeneratorTest < Rails::Generators::TestCase
     end
   end
 
-  def test_inclusion_of_method_source
-    run_generator
-    assert_file "Gemfile" do |content|
-      assert_gem 'method_source'
-    end
-  end
-
   def test_template_from_dir_pwd
     FileUtils.cd(Rails.root)
     assert_match(/It works from file!/, run_generator([destination_root, "-m", "lib/template.rb"]))