app/views/projects/_roles.html.erb
<% @roles.each do |role| %>
<h2><%= role.users.size > 1 ? role.name.humanize.pluralize : role.name.humanize %></h2>
<ul>
<% role.users.each do |user| %>
<li>
<%= link_to user.name, profile_path(user) %> (<%= user.login %>)
<% if can? :manage, role %>
<%= remote_button "Remove", remove_role_project_path(id: @project, role: {user: user.id, authorizable_type: role.name}), { update: "#role_list" }, {class: 'btn btn-danger'} %>
<% end %>
</li>
<% end %>
</ul>
<% end %>