Update README.md
Merge pull request #9 from DavidMikeSimon/master

Automatically associating OpenIdEntity with correct user class
Merge pull request #10 from DavidMikeSimon/master

Fixed missing field name in automatic OpenIdentity association
Better handling of missing user scenario
Merge pull request #11 from DavidMikeSimon/no_such_user_fix

Better handling of missing user scenario