Rails has_many :through association. Remove an association with a link?
===

I've got an Events model and a Users model joined through an Attendees model. I have figured out how to "Attend" an event as an authenticated user. But what I can't figure out is a nice way to "Withdraw" from an event. I'm sure this is something trivial that I'm missing but what better way to make an entrance into StackOverflow than to ask something trivial? Oh I have been searching railscasts and SO for hours...

Thanks!

**views/events/show.html.erb**

    <p><strong>Attendees: </strong>
    	<ul>
    		<% for attendee in @event.users %>
    			<% if attendee.username == current_user.username %>
    				<li><strong><%= attendee.username %></strong>
    					<%= link_to 'Withdraw From Event', withdraw_event_path(@event.id), :method => :post, :class => 'btn btn-danger' %>
    					<%= link_to 'Destroy', @attendee, confirm: 'Are you sure?', method: :delete, :class => 'btn btn-danger' %>
    				</li>
    			<% else %>
    				<li><%= attendee.username %></li>
    			<% end %>
    		<% end %>	
    	</ul>
    </p>

**/controllers/events_controller.rb**

      def attend
        @event = Event.find(params[:id])
        current_user.events << @event
        redirect_to @event, notice: 'You have promised to attend this event.'
      end
      
      def withdraw
        # I can't get this to work
        redirect_to @event, notice: 'You are no longer attending this event.'
      end

**models/event.rb**

    class Event < ActiveRecord::Base
        attr_accessible :name, :location
        belongs_to :users
 	
        has_many :attendees, :dependent => :destroy
        has_many :users, :through => :attendees

**models/user.rb**

    class User < ActiveRecord::Base
        has_many :events
    
        has_many :attendees, :dependent => :destroy
        has_many :events, :through => :attendees

**models/attendee.rb**

    class Attendee < ActiveRecord::Base
        belongs_to :event
        belongs_to :user
    	
        attr_accessible :user_id, :event_id
      
        # Make sure that one user cannot join the same event more than once at a time.
        validates :event_id, :uniqueness => { :scope => :user_id }
      
    end