This should be done automatically by the GitCentric installer, but if you try to run the psql command and get an error regarding libpq.so.5, you need to update your LD_LIBRARY_PATH to point to the lib subdirectory under the AccuRev version of PostgreSQL:
> export LD_LIBRARY_PATH=<ac_home>/postgresql/lib:$LD_LIBRARY_PATH
where <ac_home> is the directory where AccuRev is installed.