Add Single Customer endpoint

lib/admin/admin-server.js

@@ -175,6 +175,14 @@ app.get('/api/customers', (req, res, next) => {
   .catch(next)
 })
 
+app.get('/api/customer/:id', (req, res, next) => {
+  return customers.getById(req.params.id)
+  .then(r => {
+    if (!r) return res.status(404).send({Error: 'Not found'})
+    return res.send(r)
+  })
+})
+
 app.use((err, req, res, next) => {
   console.error(err)