Fixed plaintext password security issue. Included gem bcrypt for
encrypting. Added column password_digest to table user. used
has_secure_password module. Replaced authenticate method in
session_controller. Wrote a new test and fixed one failing test.
Merge pull request #6 from Gbeschbacher/master

Fixing plaintext password security issue - achtung, alte user können nicht mehr einloggen!
siehe http://stackoverflow.com/questions/7867742/rails-3-1-1-has-secure-password-digest-cant-be-blank für eine lösung