Docker failure over PostgreSQL version

[ain]

Steps to reproduce:

1. Clone repo

2. Start Docker Compose

    $ docker-compose up 
   

What happens:

Recreating fatfreecrm_db_1
Recreating fatfreecrm_web_1
Attaching to fatfreecrm_web_1, fatfreecrm_db_1
web_1  | dpkg: warning: failed to open configuration file '/root/.dpkg.cfg' for reading: Permission denied
web_1  | dpkg: warning: failed to open configuration file '/root/.dpkg.cfg' for reading: Permission denied
db_1   | FATAL:  database files are incompatible with server
db_1   | DETAIL:  The data directory was initialized by PostgreSQL version 9.5, which is not compatible with this version 9.6.2.
fatfreecrm_db_1 exited with code 1

What should happen: microservices should start without failure.

[ain]

This is resolved in #601.