Credit goes to James Smith (http://loopj.com) for the jquery tokenInput plugin
gem 'active_admin_tokeninput'
Add this line to the active_admin model file, which sets up the autocomplete route.
ActiveAdmin.register Post do
tag_autocomplete
end
Add this to your activeadmin form if it's a has_many reationship
f.input :posts, as: :has_many_token
Otherwise if it's a belongs_to
f.input :author, as: :belongs_to_token
If you need to define your own autocomplete path
f.input :posts, as: :belongs_to_token, autocomplete_path: autocomplete_admin_author_posts_path