Logging on the database.

Currently, beyond logs to the file and console. We need to save the log
on the mongodb. Sadly, we have to make a new appender because logback
doesn't provide it.

First time I tried to create new class on beyond framework. But it's
not possible.
Play framework dynamically compile the class on the development mode,
but logback needs compiled class before using it.

So I create new project
https://github.com/sgkim126/logback-mongodb-appender and add the jar
file to beyond.