Add jenkins user to postgres as super user

chef-jenkins-postgres.rb

execute "usermod jenkins -aG postgres" do
  not_if "groups jenkins | grep postgres"
end

execute "createuser jenkins --superuser --no-password" do
  user "postgres"
  group "postgres"
  cwd "/var/lib/postgresql"

  not_if "psql postgres -tAc \"SELECT 1 FROM pg_roles WHERE rolname='jenkins'\" | grep 1",
    :cwd => "/var/lib/postgresql",
    :user => "postgres",
    :group => "postgres"
end