add docs page on versions and upgrading

Signed-off-by: JENNIFER RONDEAU <jrondeau@heptio.com>

docs/versions.md

@@ -0,0 +1,18 @@
+# Upgrading Ark versions
+
+Ark supports multiple concurrent versions. Whether you're setting up Ark for the first time or upgrading to a new version, you need to pay careful attention to versioning. This doc page is new as of version 0.10.0, and will be updated with information about subsequent releases.
+
+## Minor versions, patch versions
+
+The documentation site provides docs for minor versions only, not for patch releases. Patch releases are guaranteed not to be breaking, but you should carefully read the [release notes][1] to make sure that you understand any relevant changes.
+
+If you're upgrading from a patch version to a patch version, you only need to update the image tags in your configurations. No other steps are needed.
+
+Breaking changes are documented in the release notes and in the documentation.
+
+## Breaking changes for version 0.10.0
+
+- See [Upgrading to version 0.10.0][2]
+
+[1]: https://github.com/heptio/ark/releases
+[2]: upgrading-to-v0.10.md