Using Ruby 1.9.2 and Rails 3 -
When attempting to use <%= error_messages_for 'story' %> I get this error:
DEPRECATION WARNING: error_messages_for was removed from Rails and is now available as a plugin. Please install it with `rails plugin install git://github.com/rails/dynamic_form.git`. (called from _app_views_stories_new_html_erb__1042605186_33967248__100840187 at C:/Ruby192/shovell/app/views/stories/new.html.erb:1)
So I did what it said and ran the plugin install. However now I have an empty dynamic_form folder at vendor/plugins. I tried using http instead of git with no luck. I also added a / at the end of the URL which worked for someone else online, but with no luck.
I added gem dynamic_form to the Gemfile and require "dynamic_form" to the application.rb as well as rerun bundle install. It shows that dynamic_form-1.1.3 is installed to `lib/ruby/gems/1.9.1/gems/' but I am still getting the same error.
The solution was as Jeremy pointed out, to simply download rails/dynamic_form on github and extract it to vendor/plugins and rename the folder "dynamic_form". The reason it didn't work for me before was because I was using someone else's modified version of dynamic form and of course not specifying it.