docs: improve teams docs (#248)

Signed-off-by: Ryota Sakamoto <[email protected]>

Author: ryota-sakamoto

docs/services/teams.md

@@ -1,11 +1,18 @@
 # Teams
 
+## Parameters
+
+The Teams notification service send message notifications using Teams bot and requires specifying the following settings:
+
+* `recipientUrls` - the webhook url map, e.g. `channelName: https://example.com`
+
+## Configuration
+
 1. Open `Teams` and goto `Apps`
 2. Find `Incoming Webhook` microsoft app and click on it
 3. Press `Add to a team` -> select team and channel -> press `Set up a connector`
 4. Enter webhook name and upload image (optional)
-5. Press `Create` then copy webhook url and store it in `argocd_notifications-secret`
-6. in `argocd-notifications-cm` ConfigMap:
+5. Press `Create` then copy webhook url and store it in `argocd-notifications-secret` and define it in `argocd-notifications-cm`
 
 ```yaml
 apiVersion: v1
@@ -18,12 +25,74 @@ data:
       channelName: $channel-teams-url
 ```
 
-7. Create subscription for your Teams integration:
+```yaml
+apiVersion: v1
+kind: Secret
+metadata:
+  name: argocd-notifications-secret
+stringData:
+  channel-teams-url: https://example.com
+```
+
+6. Create subscription for your Teams integration:
 
 ```yaml
 apiVersion: argoproj.io/v1alpha1
 kind: Application
 metadata:
   annotations:
     notifications.argoproj.io/subscribe.on-sync-succeeded.teams: channelName
-```
+```
+
+## Templates
+
+![](https://user-images.githubusercontent.com/18019529/114271500-9d2b8880-9a4c-11eb-85c1-f6935f0431d5.png)
+
+Notification templates can be customized to leverage teams message sections, facts and potentialAction [feature](https://docs.microsoft.com/en-us/microsoftteams/platform/webhooks-and-connectors/how-to/connectors-using).
+
+```yaml
+template.app-sync-succeeded: |
+  teams:
+    sections: |
+      [{
+        "facts": [
+          {
+            "name": "Sync Status",
+            "value": "{{.app.status.sync.status}}"
+          },
+          {
+            "name": "Repository",
+            "value": "{{.app.spec.source.repoURL}}"
+          }
+        ]
+      }]
+    potentialAction: |-
+      [{
+        "@type":"OpenUri",
+        "name":"Operation Details",
+        "targets":[{
+          "os":"default",
+          "uri":"{{.context.argocdUrl}}/applications/{{.app.metadata.name}}?operation=true"
+        }]
+      }]
+    title: Application {{.app.metadata.name}} has been successfully synced
+    text: Application {{.app.metadata.name}} has been successfully synced at {{.app.status.operationState.finishedAt}}.
+```
+
+### facts field
+
+You can use `facts` field instead of `sections` field.
+
+```yaml
+template.app-sync-succeeded: |
+  teams:
+    facts: |
+      [{
+        "name": "Sync Status",
+        "value": "{{.app.status.sync.status}}"
+      },
+      {
+        "name": "Repository",
+        "value": "{{.app.spec.source.repoURL}}"
+      }]
+```