Ok, so you followed the documentation from Odoo.com, here or any other blog & installed Odoo. For some reason, you get an internal server error and logs tell that role Odoo is missing.
Not a problem. In this blog post, I am going to show you how to overcome OperationalError: FATAL: role "odoo" does not exist
This usually happens when installing Odoo from the package and it is related to missing PostgreSQL user.
Simply copy and paste this in your terminal:
1) sudo su postgres
2) createuser odoo -s
3) psql template1