Can we add syntax for references auto create index or not.

When we create table, some column use foreign key references.
Now PostgreSQL don't create index for the FK, and there is no problem.
But when some body need the index to speed up the query within these APP,
they need to add the index manual one-by-one when has many tables.
If we can add syntax for auto create index for FK by user's choose, and
default not create?