Add some information to README.md
Add some information to README.md

R=kustermann@google.com
BUG=

Review URL: https://chromereviews.googleplex.com/61667013

dart-lang/appengine,dart-lang/appengine,kevmoo/appengine,exitlive/appengine,kevmoo/appengine,exitlive/appengine,exitlive/appengine,kevmoo/appengine,kevmoo/appengine