Assorted fixed from logbot.g0v.tw

Hi - Thanks so much for this amazing logbot!

The application.js change was brought about due to duplicated messages received from a dropped / restarted server.

There's also three environment variables introduced to `logbot.rb.example`; the motivation is that the user can run it with `docker run -e LOGBOT_NICK=xxx -e LOGBOT_CHANNELS=#x,#y,#z -e LOGBOT_SERVER=38.229.70.20 audreyt/logbot ` and get a running Redis & logbot in port 5000.