Added little documentation.

app/models/token.rb

@@ -1,9 +1,46 @@
 # Copyright (C) 2012-2014 Zammad Foundation, http://zammad-foundation.org/
 
 class Token < ActiveRecord::Base
-  before_create           :generate_token
+  before_create :generate_token
+  belongs_to    :user
 
-  belongs_to              :user
+=begin
+
+create new token
+
+  token = Token.create( action: 'PasswordReset', user_id: user.id )
+
+returns
+
+  the token
+
+create new persistent token
+
+  token = Token.create(
+    action:     'CalendarSubscriptions',
+    persistent: true,
+    user_id:    user.id,
+  )
+
+in case if you use it via an controller, e. g. you can verify via "curl -H "Authorization: Token token=33562a00d7eda2a7c2fb639b91c6bcb8422067b6" http://...
+
+returns
+
+  the token
+
+=end
+
+=begin
+
+check token
+
+  user = Token.check( action: 'PasswordReset', name: 'TheTokenItSelf' )
+
+returns
+
+  user for who this token was created
+
+=end
 
   def self.check( data )
 
@@ -30,7 +67,7 @@ class Token < ActiveRecord::Base
   def generate_token
 
     loop do
-      self.name = SecureRandom.hex(20)
+      self.name = SecureRandom.hex(30)
 
       break if !Token.exists?( name: name )
     end