Added Jest for testing both front and backend

server/presenters/user.test.js

@@ -0,0 +1,19 @@
+import presentUser from './user';
+
+import ctx from '../../__mocks__/ctx';
+
+it('presents a user', async () => {
+  const user = await presentUser(
+    ctx,
+    {
+      id: '123',
+      name: 'Test User',
+      username: 'testuser',
+      slackData: {
+        image_192: 'http://example.com/avatar.png',
+      },
+    },
+  );
+
+  expect(user).toMatchSnapshot();
+});