Formatting Controller Response in Rails with Ember $.getJSON request

Disclaimer: New to Ember (and by no means a seasoned Rails dev)

I am building a simple Ember app using a Rails backend to query a third party API. My controller is receiving the params from the GET request, but I get a 500 error telling me that I am calling a render/redirect multiple times in this action. I really want a JSON response sent back to my Ember controller.

// Ember controller

export default Ember.Controller.extend({

  actions: {
    getGif: function(){
      $.getJSON("http://localhost:3000/gifs?q=cats", function(result){
       var embedGif = result
        $('#some-id').append(embedGif);
      }) 
    }
  }
});

---

class PostController < ApplicationController


  def gifs
    searchterm = params[:q]
    split_string = searchterm.split(" ")
    if split_string.length > 1
      slug = split.string.join("+")
    else
      slug = searchterm
    end
    response = HTTParty.get("http://ift.tt/1LSTq4y")
    response["data"].each do |gif|
      url = gif["images"]["fixed_height"]["url"] 
    respond_with(url) |format|
        format.json
    end
    end
  end
end