Replace kubegres with stackgres in miniflux config

apps/miniflux/app.yaml

@@ -6,6 +6,6 @@ metadata:
 resources:
   - app/namespace.yaml
   - app/miniflux-sealedsecret.yaml
-  - app/postgres.yaml
+  - app/stackgres.yaml
   - app/release.yaml
   - app/route.yaml

apps/miniflux/app/stackgres.yaml

@@ -0,0 +1,21 @@
+apiVersion: stackgres.io/v1
+kind: SGCluster
+metadata:
+  namespace: miniflux
+  name: cluster
+spec:
+  postgres:
+    version: latest
+  instances: 2
+  pods:
+    persistentVolume:
+      size: '5Gi'
+      storageClass: ebs-ssd
+  configurations:
+    credentials:
+      users:
+        superuser:
+          password:
+            name: miniflux-secret
+            key: postgres-password
+