Install PostgreSQL(PGDG) to Amazon Linux.

Vagrantfile.rb

Vagrant.configure(2) do |config|
  config.vm.provision :chef_solo do |chef|
    chef.cookbooks_path = %w(site-cookbooks cookbooks)
    chef.add_recipe 'postgresql'

    chef.json = {
      postgresql: {
        version: '9.3',
        enable_pgdg_yum: true,
        client: { packages: %w(postgresql93-devel) },
        pgdg: {
          repo_rpm_url: {
            '9.3' => {
              amazon: {
                '2014' => {
                  "x86_64" => 'http://yum.postgresql.org/9.3/redhat/rhel-6-x86_64/pgdg-redhat93-9.3-1.noarch.rpm'
                }
              }
            }
          }
        }
      }
    }
  end
end