Multiple check box with has many

multi_checkbox.erb

<%= form_for(@user) do |f| %>
<div class="user_container">
 
    <%= f.label :intrests %>
    <ul>
	<% Interest.all.each do |interest| %>
	  <li>
	  <label class="li">
	         <%= check_box_tag :intrest_ids, intrest.id, @user.interests.include?(interest), :name => 'user[intrest_ids][]' %> <u><%= intrest.title %></u>
	  </label>
	  </li>
	<% end %>
    </ul>
</div>
<% end %>