Hi,
I had to battle quite a bit to find how to load acts_as_taggable without using require_gem.
where I previously had
require_gem 'acts_as_taggable'
I tried replacing by the obvious
gem 'acts_as_taggable' require 'acts_as_taggable'
this failed miserably. The trick is that the acts_as_taggable module is in a file named taggable in the lib directory of the gem. so to get it to work you have to replace the require with :
require 'taggable'
Now you can use acts_as_taggable without any warnings. While this may seem obvious to many here, I hope it prevents the waste of a couple hours to a few other newbies thus my post.
Back to tracking every last of these deprecation warnings now that my
test pass again 
Jean