backport: rateLimitPerUser (#2874)

src/structures/TextChannel.js

@@ -36,6 +36,12 @@ class TextChannel extends GuildChannel {
      * @type {?Snowflake}
      */
     this.lastMessageID = data.last_message_id;
+
+    /**
+     * The ratelimit per user for this channel
+     * @type {number}
+     */
+    this.rateLimitPerUser = data.rate_limit_per_user || 0;
   }
 
   /**
@@ -97,6 +103,16 @@ class TextChannel extends GuildChannel {
     }
   }
 
+  /**
+   * Sets the rate limit per user for this channel.
+   * @param {number} rateLimitPerUser The new ratelimit
+   * @param {string} [reason] Reason for changing the channel's ratelimits
+   * @returns {Promise<TextChannel>}
+   */
+  setRateLimitPerUser(rateLimitPerUser, reason) {
+    return this.edit({ rateLimitPerUser }, reason);
+  }
+
   // These are here only for documentation purposes - they are implemented by TextBasedChannel
   /* eslint-disable no-empty-function */
   send() { }