FEATURE: User page refactor

Re-organise user page so it is easier to find interesting info
split it into tabs

- Introduce notifications and messages tabs
- Stop couting stuff for the user page to speed up rendering
- Suppress more information when viewing your own profile

db/migrate/20151219045559_add_has_messages_to_groups.rb

@@ -0,0 +1,15 @@
+class AddHasMessagesToGroups < ActiveRecord::Migration
+  def up
+    add_column :groups, :has_messages, :boolean, default: false, null: false
+
+    execute <<SQL
+    UPDATE groups g SET has_messages = true
+    WHERE exists(SELECT group_id FROM topic_allowed_groups WHERE group_id = g.id)
+SQL
+
+  end
+
+  def down
+    remove_column :groups, :has_messages
+  end
+end