update waiter templates

app/assets/javascripts/waiter/app/templates/product_categories.emblem

@@ -1,9 +1,9 @@
-each product_category in controller
+each model as |product_category|
   if product_category.products
     h5= product_category.name
     hr
     ul.product_category-products
-      each product in product_category.products
+      each product_category.products as |product|
         li
           a{action "addProduct" product } href="#" = product.name
 

app/assets/javascripts/waiter/app/templates/section.emblem

@@ -1,6 +1,6 @@
 .row
   .section-tables.small-12.medium-6.large-4.columns
-    each table in tables
+    each tables as |table|
       = link-to 'table' table class="panel section-table"
         = table.number
   .small-12.medium-6.large-4.columns= render 'product_categories'

app/assets/javascripts/waiter/app/templates/sections.emblem

@@ -1,6 +1,6 @@
 dl.sub-nav
   dt= t 'model.section'
-  each section in controller
+  each model as |section|
     view App.SectionHeaderView context=section
   else
     dd No available sections