make changeSets Sets (duh) to avoid repetition

app/models/merged/change_set.rb

@@ -13,9 +13,9 @@ module Merged
 
     def zero
       [Page, Section, Card].each { |m| m.reload(true) }
-      @adds = []
-      @edits = []
-      @deletes = []
+      @adds = Set.new
+      @edits = Set.new
+      @deletes = Set.new
     end
 
     def add( type , text)

app/views/merged/changes/index.haml

@@ -27,6 +27,7 @@
             %td.px-4.py-2.text-gray-700
               - changeset(type , element).each do |name|
                 =name.last
+                %br
 
 .grid.grid-cols-3.bg-white
   .items-center.justify-center.col-span-2