Add fullstack example

examples/fullstack/backend/index.js

@@ -0,0 +1,17 @@
+const express = require('express')
+const app = express()
+const port = 3000
+const pgp = require('pg-promise')(/* options */)
+const db = pgp(process.env.DB_CONNECTION_STRING)
+
+
+app.get('/api', async (req, res) => {
+  let data = await db.one('SELECT $1 AS value', 123)
+
+  res.json({hello: "world", data: data.value})
+})
+
+app.listen(port, (res) => {
+  
+  console.log(`Example app listening on port ${port}`)
+})