Added newline to appended gem config in Gemfile

Signed-off-by: NYehuda Katz <yehudakatz@YK.local>

railties/lib/rails/generators/actions.rb

@@ -81,7 +81,7 @@ def gem(*args)
         end
 
         in_root do
-          append_file "Gemfile", "gem #{parts.join(", ")}", :verbose => false
+          append_file "Gemfile", "gem #{parts.join(", ")}\n", :verbose => false
         end
       end