Added basic registration with statistics

The code below accepts the data from the fb queue and creates a user in the database (firebase) as well as performs various counter actions upon transaction.

Next step is to integrate sending email from @MattyKuzyk and enable queue listener

![http://i.imgur.com/qZP8ddg.png](http://i.imgur.com/qZP8ddg.png)
So, the default value for a key is `null` but im making it a list and then updating the list by keeping the uniques only. This null check avoids the very first concatenation err