How to update postgres (default user) password and rails+ruby compatibility table

First login into postgres server

$ sudo -u postgres psql

Change the password

ALTER USER postgres WITH ENCRYPTED PASSWORD 'postgres';

Then go and change the conf

$sudo nano /etc/postgresql/9.5/main/pg_hba.conf

Change from peer to md5
Instead of this

local   postgres   postgres   peer

Change to this

local   postgres   postgres   md5

Then restart server

$ sudo service postgresql restart

Credits:
https://stackoverflow.com/a/69778580/379779

https://www.fastruby.io/blog/ruby/rails/versions/compatibility-table.html