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
```

appinfo/database.xml

@@ -39,13 +39,13 @@
 				<name>user</name>
 				<type>text</type>
 				<notnull>true</notnull>
-				<length>255</length>
+				<length>64</length>
 			</field>
 			<field>
 				<name>affecteduser</name>
 				<type>text</type>
 				<notnull>true</notnull>
-				<length>255</length>
+				<length>64</length>
 			</field>
 			<field>
 				<name>app</name>