Update Slack integration configuration

doc/integration/slack.md

@@ -6,15 +6,17 @@ To enable Slack integration you must create an Incoming WebHooks integration on
 
 1.  [Sign in to Slack](https://slack.com/signin)
 
-1.  Select **Configure Integrations** from the dropdown next to your team name.
+1.  Select **Apps & Custom Integrations** from the dropdown next to your team name.
 
-1.  Select the **All Services** tab
+1.  Click the **Configure** link (right-upper corner).
 
-1.  Click **Add** next to Incoming Webhooks
+1.  Select the **Custom integrations** tab.
 
-1.  Pick Incoming WebHooks
+1.  Click the **Incoming WebHooks** row.
 
-1.  Choose the channel name you want to send notifications to
+1.  Click the **Add configuration** button.
+
+1.  Choose the channel name you want to send notifications to.
 
 1.  Click **Add Incoming WebHooks Integration**
     - Optional step; You can change bot's name and avatar by clicking modifying the bot name or avatar under **Integration Settings**.