Big refactoring of registration

- Added datatable gem
- Addaed datatable to events, users (#422), registrations

app/models/user.rb

@@ -16,7 +16,8 @@ class User < ActiveRecord::Base
   has_many :openids
 
   attr_accessible :email, :password, :password_confirmation, :remember_me, :role_id, :role_ids,
-                  :name, :email_public, :biography, :nickname, :affiliation, :is_admin
+                  :name, :email_public, :biography, :nickname, :affiliation, :is_admin,
+                  :tshirt, :mobile, :volunteer_experience, :languages
 
   has_many :event_users, dependent: :destroy
   has_many :events, -> { uniq }, through: :event_users