Add editing feature to custom command

Also edit the default if argument isn't recognised.

util/editCustomCommand.js

@@ -0,0 +1,20 @@
+const fs = require('fs')
+module.exports = function(customName, author, newCustomMessage){
+	const customPath = './data/customCommands.json';
+	let sendText = "This custom command does not exist.";
+	let json = fs.readFileSync(customPath, 'utf8');
+	let customCommands = JSON.parse(json)
+	customCommands.forEach(function (customCommand) {
+		if (customCommand.customName === customName) {
+			if(customCommand.author === author){
+				customCommand.customMessage = newCustomMessage;
+				fs.writeFileSync(customPath, JSON.stringify(customCommands, null, 4))
+				sendText = `${customName} has been updated.`;
+			}else {
+				sendText = "You do not own this custom command.\nOnly the one who created the custom command can edit it."
+			}
+		}
+	});
+
+	return sendText;
+}