[Feat] User service init

References #61.

server/services/user-service/src/index.ts

@@ -0,0 +1,29 @@
+import express from 'express';
+import bodyParser from 'body-parser';
+import makeExpressCallback from '../../core/express-callback';
+import config from '../../core/config';
+import {
+  postAuthenticateSendSms,
+  postAuthenticateVerifyToken,
+  notFound,
+} from './interfaces/controllers';
+
+const apiRoot = config.apiRoot;
+const app = express();
+app.use(bodyParser.json());
+
+app.post(
+    `${apiRoot}/users/authenticate/step1`,
+    makeExpressCallback(postAuthenticateSendSms),
+);
+app.post(
+    `${apiRoot}/users/authenticate/step1`,
+    makeExpressCallback(postAuthenticateVerifyToken),
+);
+app.use(makeExpressCallback(notFound));
+
+app.listen(3004, () => {
+  console.log('Users service started on "/api/users"...');
+});
+
+export default app;