jQuery UI AutoComplete

controller.rb

class IngredientsController < ApplicationController
  def index
    @ingredients = if params[:term]
      Ingredient.where("name LIKE ?", "%#{params[:term]}%")
    else
      Ingredient.all.ordered
    end
    respond_to do |format|
      format.html
      format.json { render json: @ingredients, root: false }
    end
  end
end

gistfile1.coffee

$ ->
  $(".autocomplete").autocomplete(
    source: $(".autocomplete").data("path")
  )

view.html.erb

<div class="control-group name-column">
  <%= f.label :name, class: 'control-label' %>
  <div class="controls">
    <%= f.fields_for :ingredient do |ingredient_form| %>
      <%= ingredient_form.text_field :name, class: "autocomplete form-control", data: { path: admin_ingredients_path } %>
    <% end %>
  </div>
</div>