Add identity field

[Jaime-alv]

Delete serial and smallserial as primary key and add identity field instead.
Allow roles to add primary key in a sql statement.

source

Don't use serial
For new applications, identity columns should be used instead.

Why not?
The serial types have some weird behaviors that make schema, dependency, and permission management unnecessarily cumbersome.

When should you?
If you need support to PostgreSQL older than version 10.
In certain combinations with table inheritance (but see there)
More generally, if you somehow use the same sequence for multiple tables, although in those cases an explicit declaration might be preferable over the serial types.