Fix pm2 monitoring

Okay huh, while digging a bit into another issue, I found what was wrong with our config and pm2's built-in monitoring! You can't use `yarn start`, because the wrapper script breaks its ability to look inside and see what's happening.

I also removed the compiler flag thing from the `start` script in `package.json`, because I think it's redundant? There's no compilation to be done in a live server.

I think I might remove monit after this? It's nice extra resilience in a sense, but it feels like extra complexity when it's doing the job `pm2` is supposed to do. (And tbh I've almost never heard of nginx crashing, and if it does it's probably a scenario worth investigating by hand.)

deploy/playbooks/setup.yml

@@ -71,8 +71,11 @@
               {
                 name: "impress-2020",
                 cwd: "/srv/impress-2020/current",
-                script: "yarn",
-                args: "start",
+                // Instead of `yarn start`, we specify the `next` binary
+                // directly, because it helps pm2 monitor our app correctly.
+                // https://github.com/vercel/next.js/discussions/10675#discussioncomment-34615
+                script: "./node_modules/.bin/next",
+                args: "start --port=3000",
                 instances: "max",
                 exec_mode: "cluster",
                 // We add `app` to the end of the filename, to avoid a pm2

package.json

@@ -60,7 +60,7 @@
   },
   "scripts": {
     "prepare": "husky install",
-    "start": "TS_NODE_COMPILER=typescript-cached-transpile next start",
+    "start": "next start",
     "dev": "yarn build-cached-data && REACT_APP_IMPRESS_LOG_IN_AS=$IMPRESS_LOG_IN_AS TS_NODE_COMPILER=typescript-cached-transpile next dev",
     "build": "yarn build-cached-data && next build",
     "vercel-build": "yum install libuuid-devel libmount-devel && cp /lib64/{libuuid,libmount,libblkid}.so.1 node_modules/canvas/build/Release/",