Change server to Puma

- I feel Puma works better than WEBrick.
  It actually does.
- Thin is not an option for me anymore. Had a lot of tproblems in another project.
- Note the security warning at Puma startup about threading:
     SECURITY WARNING: No secret option provided to Rack::Session::Cookie.
     This poses a security threat. It is strongly recommended that you
     provide a secret to prevent exploits that may be possible from crafted
     cookies. This will not be supported in future versions of Rack, and
     future versions will even invalidate your existing user cookies.
Add permalink field to DB
Merge branch 'dev' about permalink branck