Sessions table creation error on MariaDB

[cappuccio]

Hi, i tried to use this module to store my sessions, but I'm encountering an error when it tries to create a dedicated table to store the sessions:

Unhandled rejection Error: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'json not null, 'expired' datetime not null)' at line 1

It is clearly due to the fact that the json format is only supported by MariaDB 10.2+.

[adarshmadrecha]

Related to #50