Fixed a bug where the Calender wasn't working in the User Admin panel

The calendar select would open but not set the new Rate field.  Turned out to
be because the Membership tab had form elements with the same id.

  #2031

app/views/users/_memberships.rhtml

@@ -34,7 +34,7 @@
         <% remote_form_for(:rate, :url => formatted_rates_path('js')) do |f| %>
 
         <%= f.text_field :amount %>
-        <%= f.hidden_field :date_in_effect, :value => Date.today.to_s %>
+        <%= f.hidden_field :date_in_effect, :value => Date.today.to_s, :id => "" %>
         <%= f.hidden_field :project_id, :value => membership.project.id %>
         <%= f.hidden_field :user_id, :value => @user.id %>
         <%= hidden_field_tag "back_url", url_for(:controller => 'users', :action => 'edit', :id => @user, :tab => 'memberships') %>