Add Mynewt specific release information

Signed-off-by: Fabio Utzig <utzig@apache.org>
diff --git a/docs/release.md b/docs/release.md
index df88efd..65d83f2 100644
--- a/docs/release.md
+++ b/docs/release.md
@@ -30,7 +30,16 @@
 
 During the time between rc1 and the final release, the only changes
 that should be merged into master are those to fix bugs found in the
-rc.
+rc and Mynewt metadata as described in the next section.
+
+## Mynewt release information
+
+On Mynewt, `newt` always fetches a versioned MCUBoot release, so after
+the rc step is finished, the release needs to be exported by modifying
+`repository.yml` in the root directory; it must be updated with the
+new release version, including updates to the pseudo keys
+(`*-(latest|dev)`). Similarly `version.yml` must have its `repo.version`
+key updated with the version number being released.
 
 ## Tagging and Release
 
@@ -60,4 +69,10 @@
 git push origin va.b.c-rcn
 ```
 
+## Update Mynewt version.yml
+
+On master `version.yml` must always have its `repo.version`
+key set to "0.0.0" to this must be done now that the release
+is finished.
+
 [semver]: http://semver.org/