app/views/layouts/_modal.html.erb
<div id="<%= id %>" class="modal fade" tabindex="-1">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<button id="modal_close_<%= id %>" type="button" class="close" data-dismiss="modal">×</button>
<%= content_for id.to_sym%>
</div>
<div class="modal-body">
<%= yield %>
</div>
</div>
</div>
</div>