(PDB-3383) CONTRIBUTING: describe integration testing
(PDB-3383) CONTRIBUTING: describe integration testing

mullr/puppetdb,rbrw/puppetdb,mullr/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,puppetlabs/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,mullr/puppetdb,mullr/puppetdb,rbrw/puppetdb,puppetlabs/puppetdb,mullr/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb