Add simple contract example

Author: tshemsedinov

JavaScript/0-contract.js

@@ -0,0 +1,16 @@
+'use strict';
+
+const promise = new Promise((resolve, reject) => {
+  setTimeout(() => {
+    resolve(100);
+    //reject(new Error('Custom error'));
+  }, 0);
+});
+
+console.dir(promise); // Promise { <pending> }
+
+promise.then((value) => {
+  console.log({ value });
+}, (error) => {
+  console.error(error);
+});