FIX: Properly associate user_profiles background urls via upload id.

`Upload#url` is more likely and can change from time to time. When it
does changes, we don't want to have to look through multiple tables to
ensure that the URLs are all up to date. Instead, we simply associate
uploads properly to `UserProfile` so that it does not have to replicate
the URLs in the table.

lib/migration/column_dropper.rb

@@ -20,17 +20,19 @@ module Migration
 
       columns.each do |column|
         column = column.to_s
-
-        DB.exec <<~SQL
-          DROP FUNCTION IF EXISTS #{BaseDropper.readonly_function_name(table, column)} CASCADE;
-          -- Backward compatibility for old functions created in the public
-          -- schema
-          DROP FUNCTION IF EXISTS #{BaseDropper.old_readonly_function_name(table, column)} CASCADE;
-        SQL
-
+        self.drop_readonly(table, column)
         # safe cause it is protected on method entry, can not be passed in params
         DB.exec("ALTER TABLE #{table} DROP COLUMN IF EXISTS #{column}")
       end
     end
+
+    def self.drop_readonly(table, column)
+      DB.exec <<~SQL
+        DROP FUNCTION IF EXISTS #{BaseDropper.readonly_function_name(table, column)} CASCADE;
+        -- Backward compatibility for old functions created in the public
+        -- schema
+        DROP FUNCTION IF EXISTS #{BaseDropper.old_readonly_function_name(table, column)} CASCADE;
+      SQL
+    end
   end
 end