Add missing API docs for Discord integration

doc/api/integrations.md

@@ -467,6 +467,40 @@ Get Custom Issue Tracker integration settings for a project.
 GET /projects/:id/integrations/custom-issue-tracker
 ```
 
+## Discord
+
+Send notifications about project events to a Discord channel.
+
+### Create/Edit Discord integration
+
+Set Discord integration for a project.
+
+```plaintext
+PUT /projects/:id/integrations/discord
+```
+
+Parameters:
+
+| Parameter | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `webhook` | string | true | Discord webhook. For example, `https://discord.com/api/webhooks/…` |
+
+### Delete Discord integration
+
+Delete Discord integration for a project.
+
+```plaintext
+DELETE /projects/:id/integrations/discord
+```
+
+### Get Discord integration settings
+
+Get Discord integration settings for a project.
+
+```plaintext
+GET /projects/:id/integrations/discord
+```
+
 ## Drone CI
 
 Drone is a Continuous Integration platform built on Docker, written in Go

lib/api/helpers/integrations_helpers.rb

@@ -340,7 +340,7 @@ module API
               required: true,
               name: :webhook,
               type: String,
-              desc: 'Discord webhook. e.g. https://discordapp.com/api/webhooks/…'
+              desc: 'Discord webhook. For example, https://discord.com/api/webhooks/…'
             }
           ],
           'drone-ci' => [