Add bootstrap diagram

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

Author: stefanprodan

content/en/flux/installation/_index.md

@@ -111,6 +111,26 @@ and configures the controllers to sync the cluster(s) state from a Git repositor
 Besides installing the controllers, the bootstrap command pushes the Flux manifests
 to the Git repository and configures Flux to update itself from Git.
 
+```mermaid
+sequenceDiagram
+  actor me as admin
+  participant cli as Flux<br><br>CLI
+  participant kube as Kubernetes<br><br>API server
+  participant flux as Flux<br><br>controllers
+  participant git as Git<br><br>repository
+  me->>cli: 1. flux bootstrap
+  cli-->>git: 2. push install config
+  cli->>kube: 3. install controllers
+  cli-->>git: 4. set deploy key
+  cli->>kube: 5. set private key
+  cli-->>git: 6. push sync config
+  cli->>kube: 7. apply sync config
+  git-->>flux: 8. pull config
+  flux->>kube: 9. reconcile
+  kube->>cli: 10. report status
+  cli->>me: 11. return status
+```
+
 If the Flux controllers are present on the cluster, the bootstrap command will perform
 an upgrade if needed. Bootstrap is idempotent, it's safe to run the command as many times as you want.