Show error in logs when DB connection failed

[abitrolly]

Right now if there is no connection to database, backend just dumps configuration and hangs with no activity. If there is no connection, it should at least give a first warning.

multy-back        | aaaaaaaaaaa
multy-back        | 2018-11-20/08:19:32.427 [ERROR] main: --------------------------------new multy back server session 
multy-back        | 2018-11-20/08:19:32.428 [INFO] main: CONFIGURATION={Name:Multy-Stage 
Database:{Address:mongodb:27000 DBUsers:userDB ... IOS:{Hard:0 Soft:0}}} 
multy-back        | 2018-11-20/08:19:32.428 [INFO] main: branch: dev 
multy-back        | 2018-11-20/08:19:32.428 [INFO] main: commit: 9e7cf01 
multy-back        | 2018-11-20/08:19:32.428 [INFO] main: build time: 2018-11-18T08:31:52+0000 
multy-back        | 2018-11-20/08:19:32.428 [INFO] main: tag: