Add superagent and supertest definitions

superagent/superagent-tests.ts

@@ -0,0 +1,12 @@
+/// <reference path="superagent.d.ts" />
+
+import superagent = require('superagent')
+
+var agent = superagent.agent();
+agent
+  .post('http://localhost:3000/signin')
+  .send({ email: 'test@dummy.com', password: 'bacon' })
+  .end((err, res) => {
+    if (err) throw err;
+    if (res.status !== 200) throw new Error('bad status ' + res.status);
+  });