Redirect to normal page on invalid referral code

We don't want to be misleading people with random referral links
that don't actually apply!

server/index.js

@@ -224,6 +224,10 @@ let homeView = async (req, res) => {
       referrer = pledge.get('anonymous') ? 'Anonymous' : pledge.get('name')
     } catch(e) {
       if (DEBUG) console.debug(`Skipping referral ${req.params.referralCode} because not found: ${e}`)
+
+      // if the referrer doesn't exist, send people to the normal homepage!
+      res.redirect('/')
+      return
     }
   }
 
@@ -687,6 +691,13 @@ The Snipette Team`
 })
 
 router.get('/thanks', async (req, res) => {
+  // validate referral code
+  if (!!req.query.ref && !await findReferrer(req.query.ref)) {
+    if (DEBUG) console.debug(`Invalid referral: redirecting to normal page`)
+    res.redirect('/thanks')
+    return
+  }
+
   let output = await twing.render('thanks.htm.twig', {
     referral_code: req.query.ref,
   })