Add Permission Overwrites deletion

src/client/rest/RESTMethods.js

@@ -317,6 +317,15 @@ class RESTMethods {
     });
   }
 
+  deletePermissionOverwrites(overwrite) {
+    return new Promise((resolve, reject) => {
+      const endpoint = `${Constants.Endpoints.channelPermissions(overwrite.channel.id)}/${overwrite.id}`;
+      this.rest.makeRequest('del', endpoint, true)
+        .then(() => resolve(overwrite))
+        .catch(reject);
+    });
+  }
+
   getChannelMessages(channel, payload = {}) {
     return new Promise((resolve, reject) => {
       const params = [];

src/structures/PermissionOverwrites.js

@@ -27,6 +27,14 @@ class PermissionOverwrites {
     this.denyData = data.deny;
     this.allowData = data.allow;
   }
+
+  /**
+   * Delete this Permission Overwrite.
+   * @returns {Promise<PermissionOverwrites, Error>}
+   */
+  delete() {
+    return this.channel.client.rest.methods.deletePermissionOverwrites(this);
+  }
 }
 
 module.exports = PermissionOverwrites;