app/views/users/edit.html.erb
<%= javascript_tag do %>
$(document).ready(function(){
$(".edit_user").submit();
});
<% end %>
<%= form_for @user, url: {action: "update"} do |f| %>
<% if session[:pending_organisation_id] %>
<input type="hidden" name="pending_organisation_id" value = "<%= session[:pending_organisation_id] %>">
<% end %>
<% end %>