document using existing secrets for the subcharts (#223)

* zammad/values.yaml: postgresql subchart now mentions how to use an existing Kubernetes secret instead of specifying passwords in the values.yaml

The example is using the secret and key names from the `secrets` section
in the values.yaml

* zammad/values.yaml: redis subchart now mentions how to use an existing Kubernetes secret instead of specifying passwords in the values.yaml

The example is using the secret and key names from the `secrets` section
in the values.yaml

* zammad/values.yaml: elasticsearch subchart now mentions how to use an existing Kubernetes secret

* zammad/Chart.yaml: increase version to 10.0.3

zammad/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v2
 name: zammad
-version: 10.0.2
+version: 10.0.3
 appVersion: 6.1.0-24
 description: Zammad is a web based open source helpdesk/customer support system with many features to manage customer communication via several channels like telephone, facebook, twitter, chat and e-mails.
 home: https://zammad.org

zammad/values.yaml

@@ -426,6 +426,11 @@ elasticsearch:
     heapSize: 512m
     masterOnly: false
     replicaCount: 1
+  # To use an existing Kubernetes secret containing the credentials,
+  # remove the comments on the lines below and adjust them accordingly
+  #
+  # security:
+  #   existingSecret: elastic-credentials
 
 # settings for the memcached subchart
 memcached:
@@ -441,12 +446,25 @@ memcached:
 # settings for the postgres subchart
 postgresql:
   auth:
-    postgresPassword: "zammad"
     username: "zammad"
-    password: "zammad"
-    database: "zammad_production"
     replicationUsername: repl_user
+    database: "zammad_production"
+
+    # Passwords
+    postgresPassword: "zammad"
+    password: "zammad"
     replicationPassword: "zammad"
+
+    # To avoid passwords in your values.yaml, you can comment out the 3 lines above
+    # and use an existing Kubernetes secret. Remove the comments on the lines below
+    # and adjust them accordingly
+    #
+    # existingSecret: postgresql-pass
+    # secretKeys:
+    #   adminPasswordKey: postgresql-admin-password
+    #   userPasswordKey: postgresql-pass
+    #   replicationPasswordKey: postgresql-replication-password
+    #
   resources: {}
     # requests:
     #   cpu: 250m
@@ -460,6 +478,12 @@ redis:
   architecture: standalone
   auth:
     password: zammad
+    # To avoid passwords in your values.yaml, you can comment out the line above
+    # and use an existing Kubernetes secret. Remove the comments on the lines below
+    # and adjust them accordingly
+    #
+    # existingSecret: redis-pass
+    # existingSecretPasswordKey: redis-password
   master:
     resources: {}
     # limits: