feat(GuildChannelManager): add addFollower (#9050)

* feat: addFolower method

* Update src/structures/NewsChannel.js

Co-authored-by: Jiralite <33201955+Jiralite@users.noreply.github.com>

---------

Co-authored-by: Jiralite <33201955+Jiralite@users.noreply.github.com>

src/managers/GuildChannelManager.js

@@ -229,6 +229,24 @@ class GuildChannelManager extends CachedManager {
     return new Webhook(this.client, data);
   }
 
+  /**
+   * Adds the target channel to a channel's followers.
+   * @param {NewsChannel|Snowflake} channel The channel to follow
+   * @param {TextChannelResolvable} targetChannel The channel where published announcements will be posted at
+   * @param {string} [reason] Reason for creating the webhook
+   * @returns {Promise<Snowflake>} Returns created target webhook id.
+   */
+  async addFollower(channel, targetChannel, reason) {
+    const channelId = this.resolveId(channel);
+    const targetChannelId = this.resolveId(targetChannel);
+    if (!channelId || !targetChannelId) throw new Error('GUILD_CHANNEL_RESOLVE');
+    const { webhook_id } = await this.client.api.channels[channelId].followers.post({
+      data: { webhook_channel_id: targetChannelId },
+      reason,
+    });
+    return webhook_id;
+  }
+
   /**
    * The data for a guild channel.
    * @typedef {Object} ChannelData

src/structures/NewsChannel.js

@@ -10,6 +10,7 @@ const { Error } = require('../errors');
 class NewsChannel extends BaseGuildTextChannel {
   /**
    * Adds the target to this channel's followers.
+   * <info>If you need the created webhook id, use {@link GuildChannelManager#addFollower}.</info>
    * @param {TextChannelResolvable} channel The channel where the webhook should be created
    * @param {string} [reason] Reason for creating the webhook
    * @returns {Promise<NewsChannel>}