New: Added Admin page (fixes #30)

fixes #30

Added .gittouch

> If src/admin/public/js/app.js doesn't exist, the site fails to load (404, can't GET /js/app.js). Reproduced on OS X and Debian Wheezy.

But app.js is still not part of the repo. Should I add it on gitignore ? or a build script?
Updated comment.