Well I figured out. I created my own controller called suggestions
Controller
class SuggestionsController < ApplicationController
autocomplete :school, :name
end
Routes
resources :suggestions do
get :autocomplete_school_name, :on => :collection
end
View
<div>
<%= f.label :school %>
<%= f.autocomplete_field :school, autocomplete_school_name_suggestions_path %>
</div>