restructure repo, separate sample app from docker configs

05-example-web-application/api-node/src/db.js

@@ -0,0 +1,25 @@
+const { Pool } = require('pg');
+
+const pool = new Pool();
+
+// the pool will emit an error on behalf of any idle clients
+// it contains if a backend error or network partition happens
+pool.on('error', (err, client) => {
+  console.error('Unexpected error on idle client', err);
+  process.exit(-1);
+});
+
+// async/await - check out a client
+const getDateTime = async () => {
+  const client = await pool.connect();
+  try {
+    const res = await client.query('SELECT NOW() as now;');
+    return res.rows[0];
+  } catch (err) {
+    console.log(err.stack);
+  } finally {
+    client.release();
+  }
+};
+
+module.exports = { getDateTime };