Summernote not working

[Rasool SB]

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.