11. Installation of postgresql-server (needed for mlstats).
  package { 'postgresql-9.1':
    ensure  => installed,
    require => Exec['apt-get update'],
  }
# 12. Installation of python-psycopg2 (needed for mlstats).
  package { 'python-psycopg2':
    ensure  => installed,
    require => Exec['apt-get update'],
  }
# 13. Installation of python-sqlalchemy (needed for sibyl).
  package { 'python-sqlalchemy':
    ensure  => installed,
    require => Exec['apt-get update'],
  }
# 14. Installation of python-jinja2 (needed for sortinghat).
  package { 'python-jinja2':
    ensure  => installed,
    require => Exec['apt-get update'],
  }
# 15. Installation of python-dateutil (needed for sortinghat).
  package { 'python-dateutil':
    ensure  => installed,
    require => Exec['apt-get update'],
 }