Change user, affecteduser from varchar 255 to 64 

cause if you are looking in the oc_user table the uid and displayname column have a max of varchar(64) so the max for you also varchar(64)
if not you are running with some databases in following error
```
innoDB': SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes
```
Update database.xml

Changed in table activity_mq col amq_affecteduser from varchar 255 to 64
Merge pull request #112 from libasys/patch-3

Change user, affecteduser from varchar 255 to 64