3 files changed, 26 insertions, 7 deletions
diff --git a/railties/lib/rails/app_loader.rb b/railties/lib/rails/app_loader.rb
index 3dc4fe5414..9e4f715ca6 100644
--- a/railties/lib/rails/app_loader.rb
+++ b/railties/lib/rails/app_loader.rb
@@ -8,15 +8,26 @@ module Rails
     RUBY = Gem.ruby
     EXECUTABLES = ["bin/rails", "script/rails"]
     BUNDLER_WARNING = <<EOS
-Looks like your app's ./bin/rails is a stub that was generated by Bundler.
+Beginning in Rails 4, Rails ships with a `rails` binstub at ./bin/rails that
+should be used instead of the Bundler-generated `rails` binstub.
 
-In Rails #{Rails::VERSION::MAJOR}, your app's bin/ directory contains executables that are versioned
-like any other source code, rather than stubs that are generated on demand.
+If you are seeing this message, your binstub at ./bin/rails was generated by
+Bundler instead of Rails.
 
-Here's how to upgrade:
+You might need to regenerate your `rails` binstub locally and add it to source
+control:
+
+ rails app:update:bin           # Bear in mind this generates other binstubs
+                                # too that you may or may not want (like yarn)
+
+If you already have Rails binstubs in source control, you might be
+inadverently overwriting them during deployment by using bundle install
+with the --binstubs option.
+
+If your application was created prior to Rails 4, here's how to upgrade:
 
   bundle config --delete bin    # Turn off Bundler's stub generator
-  rails app:update:bin          # Use the new Rails 5 executables
+  rails app:update:bin          # Use the new Rails executables
   git add bin                   # Add bin/ to source control
 
 You may need to remove bin/ from your .gitignore as well.
diff --git a/railties/lib/rails/generators/rails/app/templates/Gemfile b/railties/lib/rails/generators/rails/app/templates/Gemfile
index 4b2842ef46..7b7bebc957 100644
--- a/railties/lib/rails/generators/rails/app/templates/Gemfile
+++ b/railties/lib/rails/generators/rails/app/templates/Gemfile
@@ -1,7 +1,11 @@
 source 'https://rubygems.org'
 git_source(:github) { |repo| "https://github.com/#{repo}.git" }
-ruby <%= "'#{RUBY_VERSION}'" %>
 
+ruby <%= "'#{RUBY_VERSION}'" -%>
+
+<% unless gemfile_entries.first.comment -%>
+
+<% end -%>
 <% gemfile_entries.each do |gem| -%>
 <% if gem.comment -%>
 
diff --git a/railties/lib/rails/generators/testing/assertions.rb b/railties/lib/rails/generators/testing/assertions.rb
index 1cabf4e28c..9ac70f60c0 100644
--- a/railties/lib/rails/generators/testing/assertions.rb
+++ b/railties/lib/rails/generators/testing/assertions.rb
@@ -113,7 +113,11 @@ module Rails
         #
         #   assert_field_default_value :string, "MyString"
         def assert_field_default_value(attribute_type, value)
-          assert_equal(value, create_generated_attribute(attribute_type).default)
+          if value.nil?
+            assert_nil(create_generated_attribute(attribute_type).default)
+          else
+            assert_equal(value, create_generated_attribute(attribute_type).default)
+          end
         end
       end
     end