Clarify official/contributed providers responsibilities

docs/provider-list.md

@@ -16,6 +16,48 @@ layout: default
 {% endfor %}
 </table>
 
+### Providers with "official support"
+
+The following providers have official support:
+
+* ACTIVEDIRECTORY_PS
+* BIND
+* CLOUDFLAREAPI
+* GCLOUD
+* NAMEDOTCOM
+* ROUTE53
+
+Official support means:
+
+* New releases will block if any of these providers do not pass integration tests.
+* The DNSControl maintainers prioritize fixing bugs in these providers (though we gladly accept PRs).
+* New features will work on these providers (unless the provider does not support it).
+* StackOverflow maintains test accounts with those providers for running integration tests.
+
+### Providers with "contributor support"
+
+The other providers are supported by community members, usually the
+original contributor.
+
+Due to the large number of DNS providers in the world, the DNSControl
+team can not support and test all providers.  Test frameworks are
+provided to help community members support their code independently.
+
+* Maintainers are expected to support their provider and/or find a new maintainer.
+* Bugs will be referred to the original contributor or their designate.
+* Maintainers should set up test accounts and regularly verify that all tests pass (`pkg/js/parse_tests` and `integrationTest`).
+* Contributors are encouraged to add new tests and refine old ones. (Test-driven development is encouraged.)
+
+Maintainers of contributed providers:
+
+* digital ocean  <!-- @Deraen -->
+* dnsimple  <!-- @aeden -->
+* gandi @TomOnTime
+* namecheap @captncraig
+* OVH <!-- @Oprax -->
+
+### Requested providers
+
 We have received requests for the following providers. If you would like to contribute
 code to support this provider, please re-open the issue. We'd be glad to help in any way.