Add a migration guide for 0.7.0

[ci skip]

docs/appendices/0.7.0-migration-guide.md

@@ -0,0 +1,13 @@
+# 0.7.0 Migration Guide
+
+## Persistent Storage
+
+We should now properly handle file ownership for mounted directories. This was enhanced in 0.7.1. See the [persistent storage documentation](/dokku/advanced-usage/persistent-storage/) for more details.
+
+## Restart Policies
+
+If you previously managed container restart policies via docker-options, these can now be managed natively via the built-in `ps` plugin. There is no migration necessary. See the [restart policy documentation](/dokku/deployment/process-management/#restart-policies) for more details.
+
+## SSH Keys
+
+Dokku now has an `ssh-keys` plugin that can be used to manage ssh keys for the `dokku` user on the host operating system. See the [user management documentation](/dokku/deployment/user-management/) for more details.

docs/getting-started/upgrading.md

@@ -6,9 +6,18 @@ If your version of dokku is pre 0.3.0 (check with `dokku version`), we recommend
 
 Before upgrading, check the migration guides to get comfortable with new features and prepare your deployment to be upgraded.
 
+### 0.5 Migration Guide
+
 - [0.5 Migration Guide](/dokku/appendices/0.5.0-migration-guide/)
+
+### 0.6 Migration Guide
+
 - [0.6 Migration Guide](/dokku/appendices/0.6.0-migration-guide/)
 
+### 0.7 Migration Guide
+
+- [0.7 Migration Guide](/dokku/appendices/0.6.0-migration-guide/)
+
 ## Upgrade Instructions
 
 If dokku was installed via `apt-get install dokku` or `bootstrap.sh` (most common), upgrade with: