Simplify sidebar and navigation

Check existence of supporter levels

app/views/admin/registrations/new.html.haml

@@ -19,7 +19,7 @@
           = p.text_field :company, :placeholder => "Company/User Group/nothing", :as => :string
 
       = f.inputs "Registration Information" do
-        - if @conference.use_supporter_levels?
+        - if @conference.use_supporter_levels? and @conference.supporter_levels.length > 0
           = f.semantic_fields_for @supporter_registration do |reg|
             = reg.input :supporter_level, :as => :select, :collection => @conference.supporter_levels
             = reg.input :code, :label => "Confirmation or registration code (if applicable)"
@@ -36,11 +36,6 @@
           %br
           = f.input :social_events, :as => :check_boxes, :label => false, :collection => @conference.social_events
 
-      - if @conference.use_dietary_choices?
-        = f.inputs "Food" do
-          = f.input :dietary_choice, :collection => [["None", nil]] + @conference.dietary_choices.map {|x| [x.title, x.id]},
-              :include_blank => false, :label => "Special Dietary Restriction"
-          = f.input :other_dietary_choice, :input_html => {:rows => "2", :class => "span6"}, :label => "Other Dietary Restictions (please describe)"
       = f.action :submit, :button_html => { :value => "Create", :class => "btn btn-primary"}
       
 :javascript