Testing new app

Hi everyone,

I've publish a new app recently, but something seems to be weird with it.
I've an simple connection with facebook that register a user in my DB, everythin seems to work for me when i test it but on 18 download no one register on the app beacuse there is no new row in Database.
I dont know if there is an hidden problem...
Maybe if one of you could try to simple connect on the app to see if it's working or not, it could be amazing.
Thanks you for your help.

Here is the app: play.google.com/store/apps/details?id=com.bsit.shareyourmind