add whoami json

no longer using raw html, but using json instead.  Now contains roles
 as well.

 Issue #10
separate logic into service

I wanted to do this in hopes of writing a unit test,
but this is very difficult given that we are dealing with the
underlying security framework and GORM.  Will have to think about
this one a bit.
Merge pull request #29 from metridoc/whoami-json

Whoami json