Add a privileged scope that allows email addresses to be returned

app/views/api/users/_user.json.jbuilder

@@ -65,5 +65,7 @@ json.user do
         json.count user.sent_messages.size
       end
     end
+
+    json.email user.email if scope_enabled?(:read_email)
   end
 end

app/views/api/users/_user.xml.builder

@@ -40,5 +40,6 @@ xml.tag! "user", :id => user.id,
                            :unread => user.new_messages.size
       xml.tag! "sent", :count => user.sent_messages.size
     end
+    xml.tag! "email", user.email if scope_enabled?(:read_email)
   end
 end