app/views/participants/add.js.erb
// E1721: Adding AJAX for adding participants to assignment
<% unless flash[:error] %>
$("#user_list").append(
"<%= j render :partial => 'participant', :locals => {participant: @participant, :userid => @participant.user_id, :controller => 'participants'} %>");
<% end %>
+$("#flash_message").html("<%= j render partial: "shared/flash_messages" %>");