Update spec/README.md

Author: cprice404

spec/README.md

@@ -5,6 +5,10 @@ You will need the following in order to run them:
 * Virtualbox
 * vagrant
 * 'sahara' gem
+* The source code for all of the dependent modules; you should clone a copy of each of these at the same level in your directory structure as your copy of puppet-postgresql.  For best results you should check out the same tag that is specified as the dependency in the puppet-postgresql `Modulefile`.  At the time of this writing, here are the github repos you'll need (but check the `Modulefile` to make sure you're up to date):
+    * stdlib : https://github.com/puppetlabs/puppetlabs-stdlib
+    * firewall : https://github.com/puppetlabs/puppetlabs-firewall
+    * apt : https://github.com/puppetlabs/puppetlabs-apt
 * A decent chunk of free disk space (~300MB per distro tested)
 * Patience :)
 
@@ -22,4 +26,4 @@ instead do something like:
     rspec ./spec/distros/ubuntu_lucid_64
 
 For some options that might speed up the testing process a bit during development,
-please see `spec/support/postgres_test_config.rb`.
+please see `spec/support/postgres_test_config.rb`.