docs: warn about branch auto-deletion (#667)

* docs: warn about branch auto-deletion

Signed-off-by: Michael Crenshaw <[email protected]>

* fix typos

Signed-off-by: Michael Crenshaw <[email protected]>

* note in both places

Signed-off-by: Michael Crenshaw <[email protected]>

---------

Signed-off-by: Michael Crenshaw <[email protected]>

Author: crenshaw-dev

docs/getting-started.md

@@ -89,7 +89,7 @@ stringData:
 > [!NOTE]
 > This Secret will need to be installed to the same namespace that you plan on creating PromotionStrategy resources in.
 
-We also need a GitRepository and ScmProvider, which is are custom resources that represents a git repository and a provider. 
+We also need a GitRepository and ScmProvider, which are custom resources that represent a git repository and a provider. 
 Here is an example of both resources:
 
 ```yaml
@@ -116,6 +116,12 @@ spec:
     name: <your-scmprovider-name>
 ```
 
+> [!IMPORTANT]
+> Make sure your staging branches (`environment/development-next`, `environment/staging-next`, etc.) are not auto-deleted
+> when PRs are merged. You can do this either by disabling auto-deletion of branches in the repository settings (in
+> Settings > Automatically delete head branches) or by adding a branch protection rule for a matching pattern such as 
+> `environment/*-next` (`/` characters are separators in GitHub's glob implementation, so `*-next` will not work).
+
 > [!NOTE]
 > The GitRepository and ScmProvider also need to be installed to the same namespace that you plan on creating PromotionStrategy 
 > resources in, and it also needs to be in the same namespace of the secret it references.

docs/tutorial-argocd-apps.md

@@ -78,6 +78,12 @@ kubectl apply -f https://github.com/argoproj-labs/gitops-promoter/releases/downl
 
 Argo provides an example repository: [https://github.com/argoproj/argocd-example-apps](https://github.com/argoproj/argocd-example-apps). Fork it!
 
+> [!IMPORTANT]
+> Make sure your staging branches (`environment/development-next`, `environment/staging-next`, etc.) are not auto-deleted
+> when PRs are merged. You can do this either by disabling auto-deletion of branches in the repository settings (in
+> Settings > Automatically delete head branches) or by adding a branch protection rule for a matching pattern such as
+> `environment/*-next` (`/` characters are separators in GitHub's glob implementation, so `*-next` will not work).
+
 ### Create a GitHub application
 
 In your GitHub account, go to Settings > Developer settings > GitHub Apps.