Revert "gems can be added or skipped from the template"

This reverts commit 8beb42cfbc41753ae4dbb91e16abcd1fb7d00356.

Conflicts:
	railties/lib/rails/generators/app_base.rb
	railties/lib/rails/generators/rails/app/app_generator.rb
	railties/test/generators/app_generator_test.rb