Count totals using database instead of manually

This is way more efficient

server/index.js

@@ -161,15 +161,10 @@ router.get('/', async (req, res) => {
   if (DEBUG) console.debug('Returning home page')
 
   // count people
-  // TODO: optimise to do using SQL only
-  let total_people = 0
-  let total_rupees = 0
-  let result = await Pledge.fetchAll()
+  let { total_people, total_rupees } = (await knex('pledges')
+    .sum('amount as total_rupees')
+    .count('* as total_people'))[0]
 
-  for (let pledge of result.models) {
-    total_people += 1
-    total_rupees += pledge.get('amount')
-  }
 
   twing.render('index.htm.twig', {
     'goal_rupees': Number(goalRupees).toLocaleString('en-IN'),