Completed 406 not acceptable

***CONTROLLER***

 # POST /course_tags/create
  def ajax_create
    respond_to do |format|
      CourseTag.create("course_id" => :course_id, "tag_id" => :tag_id)
    end
  end


***BUTTON HAML***

%button.btn.btn-lg.tag-button{ "data-selected-tag" => tag.id, "data-selected-course" => @course.id}


***COFFEESCRIPT***

$ ->
  changeCourseTag = (element, courseTagExists, tagId, courseId) ->
    if courseTagExists
      $(element).removeClass("btn-success")
      $(element).addClass("btn-danger")
    else
      $(element).removeClass("btn-danger")
      $.ajax
        url: "/course_tags/create"
        type: "POST"
        data:
          course_id: courseId
          tag_id: tagId

        success: (data) ->
          $(element).addClass "btn-success"
          return


  $(".tag-button").click (e) ->
    e.preventDefault()
    tagId = $(this).data("selected-tag")
    courseId = $(this).data("selected-course")
    courseTagExists = $(this).hasClass("btn-success")
    changeCourseTag(this, courseTagExists, tagId, courseId)