Add sample usage for postgresql::server class.
Add sample usage for postgresql::server class.

I had some issues trying to connect to the server, managed with
defaults:

  vagrant@precise32:~$ psql
  psql: FATAL:  role "vagrant" does not exist
  vagrant@precise32:~$ psql -U postgres
  psql: FATAL:  Peer authentication failed for user "postgres"
  vagrant@precise32:~$ psql -U postgres -h 127.0.0.1
  psql: FATAL:  pg_hba.conf rejects connection for host "127.0.0.1", user
  "postgres", database "postgres", SSL on
  FATAL:  pg_hba.conf rejects connection for host "127.0.0.1", user
  "postgres", database "postgres", SSL off
  vagrant@precise32:~$ psql -U postgres -h /var/run/postgresql
  psql: FATAL:  Peer authentication failed for user "postgres"

After some trial and error I found out that the reasons for this was
restrictive permissions on the unix socket (which isn't bad at all):

  vagrant@precise32:~$ ls -l /var/run/postgresql/
  total 4
  -rw------- 1 postgres postgres 5 Oct 16 20:16 9.1-main.pid

So I though I send some usage examples to help noops like myself to a
quicker start with your module :-)

cdenneen/puppetlabs-postgresql,hasegeli/puppetlabs-postgresql,DSI-Ville-Noumea/puppetlabs-postgresql,petems/puppetlabs-postgresql,javierwilson/puppetlabs-postgresql,BobVanB/puppetlabs-postgresql,skyscrapers/puppetlabs-postgresql,downsj2/puppetlabs-postgresql,david-caro/puppetlabs-postgresql,thunderkeys/puppetlabs-postgresql,puppetlabs/puppetlabs-postgresql,gfokkema/puppetlabs-postgresql,genome/puppetlabs-postgresql,dealnews/puppetlabs-postgresql,cdenneen/puppetlabs-postgresql,DavidS/puppetlabs-postgresql,phervieux/puppetlabs-postgresql,redhat-cip/puppetlabs-postgresql,buzzdeee/puppetlabs-postgresql,PierreR/puppetlabs-postgresql,hasegeli/puppetlabs-postgresql,krishnaod/puppet-postgresql,MelanieGault/puppetlabs-postgresql,cyberious/puppetlabs-postgresql,jantman/puppetlabs-postgresql,cybercom-finland/puppetlabs-postgresql,genome/puppetlabs-postgresql,infoxchange/puppetlabs-postgresql,cybercom-finland/puppetlabs-postgresql,infopro-digital/puppetlabs-postgresql,cyberious/puppetlabs-postgresql,Puppet-Finland/puppetlabs-postgresql,PierreR/puppetlabs-postgresql,SUNET/puppetlabs-postgresql,tphoney/puppetlabs-postgresql,jbehrends/puppetlabs-postgresql,DSI-Ville-Noumea/puppetlabs-postgresql,gfokkema/puppetlabs-postgresql,BobVanB/puppetlabs-postgresql,hunner/puppetlabs-postgresql,tdevelioglu/puppetlabs-postgresql,Puppet-Finland/puppetlabs-postgresql,covermymeds/puppetlabs-postgresql,redhat-cip/puppetlabs-postgresql,phervieux/puppetlabs-postgresql,qha/puppetlabs-postgresql,skyscrapers/puppetlabs-postgresql,downsj2/puppetlabs-postgresql,MelanieGault/puppetlabs-postgresql,david-caro/puppetlabs-postgresql,progserega/puppetlabs-postgresql,nickchappell/puppetlabs-postgresql,GoozeyX/puppetlabs-postgresql,GoozeyX/puppetlabs-postgresql,paneidos/puppetlabs-postgresql,researchgate/puppetlabs-postgresql,holstvoogd/puppetlabs-postgresql,duritong/puppetlabs-postgresql,javierwilson/puppetlabs-postgresql,DavidS/puppetlabs-postgresql,theforeman/puppetlabs-postgresql,petems/puppetlabs-postgresql,buzzdeee/puppetlabs-postgresql,dealnews/puppetlabs-postgresql,jbehrends/puppetlabs-postgresql,thunderkeys/puppetlabs-postgresql,nickchappell/puppetlabs-postgresql,cybercom-finland/puppetlabs-postgresql,nickchappell/puppetlabs-postgresql,DSI-Ville-Noumea/puppetlabs-postgresql,Puppet-Finland/puppetlabs-postgresql,fuel-infra/puppetlabs-postgresql,fuel-infra/puppetlabs-postgresql,BobVanB/puppetlabs-postgresql,cyberious/puppetlabs-postgresql,SUNET/puppetlabs-postgresql,underscorgan/puppetlabs-postgresql,phervieux/puppetlabs-postgresql,infopro-digital/puppetlabs-postgresql,covermymeds/puppetlabs-postgresql,npwalker/puppetlabs-postgresql,bmjen/puppetlabs-postgresql,krishnaod/puppet-postgresql,hasegeli/puppetlabs-postgresql,mhaskel/puppetlabs-postgresql,progserega/puppetlabs-postgresql,kbarber/puppetlabs-postgresql,thunderkeys/puppetlabs-postgresql,bmjen/puppetlabs-postgresql,david-caro/puppetlabs-postgresql,researchgate/puppetlabs-postgresql,infopro-digital/puppetlabs-postgresql,gfokkema/puppetlabs-postgresql,dealnews/puppetlabs-postgresql,qha/puppetlabs-postgresql,tdevelioglu/puppetlabs-postgresql,hunner/puppetlabs-postgresql,underscorgan/puppetlabs-postgresql,cavaliercoder/puppetlabs-postgresql,tphoney/puppetlabs-postgresql,jbehrends/puppetlabs-postgresql,theforeman/puppetlabs-postgresql,cavaliercoder/puppetlabs-postgresql,underscorgan/puppetlabs-postgresql,cdenneen/puppetlabs-postgresql,infoxchange/puppetlabs-postgresql,fuel-infra/puppetlabs-postgresql,theforeman/puppetlabs-postgresql,npwalker/puppetlabs-postgresql,puppetlabs/puppetlabs-postgresql,skyscrapers/puppetlabs-postgresql,buzzdeee/puppetlabs-postgresql,mhaskel/puppetlabs-postgresql,bmjen/puppetlabs-postgresql,infoxchange/puppetlabs-postgresql,kbarber/puppetlabs-postgresql,kbarber/puppetlabs-postgresql,tdevelioglu/puppetlabs-postgresql,puppetlabs/puppetlabs-postgresql,holstvoogd/puppetlabs-postgresql,GoozeyX/puppetlabs-postgresql,paneidos/puppetlabs-postgresql,progserega/puppetlabs-postgresql,holstvoogd/puppetlabs-postgresql,tphoney/puppetlabs-postgresql,downsj2/puppetlabs-postgresql,cavaliercoder/puppetlabs-postgresql,petems/puppetlabs-postgresql,researchgate/puppetlabs-postgresql,SUNET/puppetlabs-postgresql,mhaskel/puppetlabs-postgresql,DavidS/puppetlabs-postgresql,javierwilson/puppetlabs-postgresql,MelanieGault/puppetlabs-postgresql,qha/puppetlabs-postgresql,mcanevet/puppet-postgresql,npwalker/puppetlabs-postgresql,covermymeds/puppetlabs-postgresql,jantman/puppetlabs-postgresql,redhat-cip/puppetlabs-postgresql,PierreR/puppetlabs-postgresql