Fix slack and document it.

README.md

@@ -76,7 +76,7 @@ This file contains a secret unique to you; te slack encryption token. You have t
 
 ```yaml
 ---
-slack_token: "YOUR_SLACK_USERNAME:YOUR_SLACK_TOKEN#CHANNEL"
+slack_token: "YOUR_SLACK_USERNAME:YOUR_SLACK_TOKEN"
 ```
 
 See [Travis documentation](https://docs.travis-ci.com/user/notifications/#configuring-slack-notifications).

templates/travis.yml.j2

@@ -40,6 +40,7 @@ script:
 notifications:
   webhooks: https://galaxy.ansible.com/api/v1/notifications/
   slack:
-    secure: {{ travis.notifications.slack.secure }}
-  on_success: change
+    secure: "{{ travis.notifications.slack.secure }}"
+    on_success: change
+    template: "%{result}: %{repository_slug}@%{branch}, build <%{build_url}|#%{build_number}> (<%{compare_url}|%{commit}>)"
   email: false