[Dbmail] Typo in INSTALL

[Matthew T. O'Connor]

Hello, I'm just getting started trying out dbmail.  I have been looking
for just such an application for a while, so I'm excited to use it. On
to the typo:

I was following the directions to setup the postgresql database and this
line is wrong:

psql -U dbmail dbmal < sql/postgresql/create_tables.pgsql

it should be:

psql -U dbmail dbmail < sql/postgresql/create_tables.pgsql
                   ^

Thanks, I hope dbmail is all I hope it is!