make sure only our own models are loaded

This is just a quick hack. we should move all engines to a dir of their own.
Merge pull request #42 from azul/bugfix/fix-migration-requiring-active-record

make sure only our own models are loaded
Merge pull request #41 from azul/feature/allow-getting-salt

Allow getting salt and proper error messages for invalid login attempts
added vim tempfiles to gitignore
initial token model and unit test
let's use safe ids instead of the default couch ones

Couch uses partly random partly sequential ids by default. We could
change that in couch config to be all random. But this is probably more
safe.
return token on successful login via api