You vagrant file should look something like this, make the required.
config.vm.define "db" do |db|   
  db.vm.hostname = "db"    
  db.vm.network "private_network", ip: "10.11.1.201", virtualbox__intnet: true
  db.vm.provider "virtualbox" do |v| 
      v.memory = 1024 
  end 
  db.vm.network "forwarded_port", guest: 22, host: 2221, id: 'ssh', auto_correct: true
    db.vm.network "forwarded_port", guest: 5432, host: 2222
  db.ssh.forward_agent = true
       config.vm.provision :shell do |shell|
 shell.inline = "mkdir -p /etc/puppet/modules;
                 puppet module install puppetlabs-postgresql"
  end
       config.vm.provision :puppet do |puppet|
    puppet.manifests_path = "puppet/manifests"
    puppet.manifest_file = "site.pp"
    puppet.module_path = "puppet/modules"
  end
    end
end