Use :rubygems shortcut as standard Gemfile's source instead of explicit URL.

Theoretically this would future-proof Gemfiles against possible (albeit unlikely) change in the rubygems URL.

Author: rossmeissl

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

@@ -1,4 +1,4 @@
-source 'https://rubygems.org'
+source :rubygems
 
 <%= rails_gemfile_entry -%>