How to get permission to debug postgres?

I have a system that uses C methods as functions in a Postgres
database. When I try to run gdb with my user account I get this:
ptrace: Operation not permitted

It looks like a permission thing. It seemed to work when I ran gdb as
the "postgres" user. I would like to continue running postgres as the
"postgres" user and not have to su postgres when I want to debug. Can
I somehow grant my user account "ptrace" permission for the process in
question? Adding myself to the "postgres" group didn't seem to help.

I found this on the ptrace man page:

EPERM  The specified process cannot be traced.  This could  be  because             the  parent has insufficient privileges (the required capability             is CAP_SYS_PTRACE); non-root processes  cannot  trace  processes             that  they  cannot  send  signals  to or those running set-user-             ID/set-group-ID programs, for obvious  reasons.   Alternatively,             the process may already be being traced, or be init(8) (PID 1).

So do I just need to give CAP_SYS_TRACE privileges to my user?  If so, how?

Thank you much.