Streaming Replication on Two Postgres Systems?
Streaming Replication will only replicate your entire cluster, and not a single database. It will also make the slave database read only, so you can't use it as your "Training Database".

If you need to do that, you need to look at something like Slony, Bucardo or Londiste.

However, those are much more complex to set up and maintain. Another option is to run two completely different clusters ("instances") on the slave - one that is the slave and one that is the training. They'll then run on different ports, with different memory pools, etc, etc. It's not great for performance to do that, but if it's just a training database that may not matter, and it's a much easier replication system to work with.