Someone

# Database administrative login by UNIX sockets
local   all         postgres                          ident sameuser

# TYPE  DATABASE    USER        CIDR-ADDRESS          METHOD

# "local" is for Unix domain socket connections only
local   all         all                               ident sameuser
# IPv4 local connections:
host    all         mycdruser   127.0.0.1/32          md5
# IPv6 local connections:
host    all         all         ::1/128               md5


postgres@dustbunny:~$ psql -U mycdruser
psql: FATAL:  Ident authentication failed for user "mycdruser"
postgres@dustbunny:~$