First update system:
 
 sudo apt-get update
 
 sudo apt-get upgrade -y
 
 sudo reboot
 
 Install mlocate to help finding the files  https://www.raspberrypi.org/forums/viewtopic.php?t=7429 
 
 sudo apt-get install mlocate 
 
 sudo updatedb
 
 
 Install the postgresql package:
 
 sudo apt-get install postgresql
 
 
 Start and enable postgresql.service:
 
 sudo systemctl start postgresql.service
 
 sudo systemctl enable postgresql.service
 
 
Create new user and database, Switch to the postgres user:
 
 sudo -u postgres -i
 
 Create user octoprint:

 createuser --interactive -P

Enter name of role to add: octoprint
Enter password for new role:
Enter it again:
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) n
Shall the new role be allowed to create more new roles? (y/n) n

Create database octoprint_filamentmanager:

 createdb -O octoprint octoprint_filamentmanager 
 
 Exit postgres, press Ctrl+D
 
 Update mlocade db
 
 sudo updatedb

 Locate postgresql.conf and edit
 
 locate postgresql.conf
 
sudo nano /xxx/xxx/postgresql.conf 

At connection settings remove # character front of 'listen_adressess' and change 'localhost' to '*'
exit by Ctrl+x, Y and enter. 

 Locate pg_hba.conf and edit
 
 locate pg_hba.conf
 
 sudo nano /xxx/xxx/pg_hba.conf
 
 add end of file    host octoprint_filamentmanager octoprint 192.168.178.1/24 md5

 Change IP to match you network  xxx.xxx.xxx.1/24 md5
 
 exit by Ctrl+x, Y and enter
 

 Restart postgresql.service 
 
 sudo systemctl reload postgresql.service
 
Install dependencies
 

sudo apt-get install libpq-dev

sudo ~/oprint/bin/pip install psycopg2

Set settings for external datava at Filament Manager