add channel.sendMessage and channel.sendTTSMessage

src/client/rest/RESTMethods.js

@@ -1,6 +1,9 @@
 'use strict';
 
 const Constants = require('../../util/Constants');
+const Structure = name => require('../../structures/' + name);
+
+const Message = Structure('Message');
 
 class RESTMethods{
 	constructor(restManager) {
@@ -32,6 +35,21 @@ class RESTMethods{
 				.catch(reject);
 		});
 	}
+
+	SendMessage(channel, content, tts, nonce) {
+		return new Promise((resolve, reject) => {
+			this.rest.makeRequest('post', Constants.Endpoints.CHANNEL_MESSAGES(channel.id), true, {
+				content, tts, nonce,
+			})
+			.then(data => {
+				let message = new Message(channel, data, this.rest.client);
+				channel._cacheMessage(message);
+				resolve(message);
+				this.rest.client.emit(Constants.Events.MESSAGE_CREATE, message);
+			})
+			.catch(reject);
+		});
+	}
 }
 
 module.exports = RESTMethods;