added string includes polyfill

fixed : #74

Author: shakee93

dist/vue-toasted.js

@@ -3,6 +3,24 @@ import animations from './animations'
 import {toastObject} from './object'
 const uuid = require('shortid');
 
+// string includes polyfill
+if (!String.prototype.includes) {
+	Object.defineProperty(String.prototype, 'includes', {
+		value: function(search, start) {
+			if (typeof start !== 'number') {
+				start = 0
+			}
+
+			if (start + search.length > this.length) {
+				return false
+			} else {
+				return this.indexOf(search, start) !== -1
+			}
+		}
+	})
+}
+
+
 let _options = {};
 let _instance = null;
 /**