+leveldb, redis, postgresql, and dummy.
+.TP
+.B \-\-migrate-auth <value>
+Migrate from current auth backend to another. Possible values are sqlite3,
+leveldb, and files.
+.TP
+.B \-\-migrate-players <value>
+Migrate from current players backend to another. Possible values are sqlite3,
+leveldb, postgresql, dummy, and files.