Ruby on Rails

am new to rails, am using summernote for my app, I have followed the whole documentation and did as per the documentation. but, the editor is not dispalying in my text_area. means it just shows a blank text area box with out any buttons, the details are below.

In my gem file:

  gem 'simple_form', '2.1.1'    gem 'summernote-rails', '0.4.0'    gem 'bootstrap-sass', '3.1.1.1'    gem 'bootstrap-will_paginate', '0.0.10'    gem 'font-awesome-sass-rails', '3.0.2.2'

In app/assets/javascripts/application.js

  //= require jquery    //= require jquery_ujs    //= require bootstrap    //= require summernote.min    //= require_tree .

in app/assets/stylesheets/application.css

  *= require_self    *= require_bootstrap    *= require_font-awesome    *= require_summernote    *= require_tree .

In my events/_form.html.erb

  <%= f.input :error_detail, label:'Summary', class:'summernote', input_html:      {class:'form-control'} %>

in my app/assets/javascripts/events.js.coffee

  $ ->      # to set summernote object    # You should change '#event_error_detail' to your textarea input id    summer_note = $('#event_error_detail')    # to call summernote editor    summer_note.summernote    # to set options    height:300    lang: 'en'    # toolbar: [              # ['insert', ['picture', 'link']], // no insert buttons              # ["table", ["table"]],              # ["style", ["style"]],              # ["fontsize", ["fontsize"]],              # ["color", ["color"]],              # ["style", ["bold", "italic", "underline", "clear"]],              # ["para", ["ul", "ol", "paragraph"]],              # ["height", ["height"]],              # ["help", ["help"]]           #]    # to set code for summernote    summer_note.code summer_note.val()    # to get code for summernote    summer_note.closest('form').submit ->    # alert $('#event_error_detail').code()    summer_note.val summer_note.code()    true

The error am getting in my firefox browser's error console

TypeError: summer_note.summernote is not a function

MY ENVIRONMENT DETAILS: Ruby 1.9.3 and Rails 3.2.8, ubuntu 12.4

Please help me where am i doing wrong.., Please I need help.