tweak: Add documentation to daemonize process

when running teddit not on a docker container.

I've generally found docker gnarly, and try not to use it. In this
case, I find pm2 to be a more convenient alternative.

It might also be interesting to have better documentation for running
this from a reverse proxy, maybe step by step, so that more people
can host these instances.

README.md

@@ -194,3 +194,16 @@ The following variables may be set to customize your deployment at runtime.
    ```
 
 Teddit should now be running at <http://localhost:8080>. 
+
+You also run teddit from a process manager like [pm2](https://www.npmjs.com/package/pm2):
+```
+## To run:
+npm install pm2 -g
+pm2 start app.js 
+
+## To run on startup:
+pm2 startup
+pm2 save
+```
+
+See also the [pm2 instructions for running a project on startup](https://pm2.keymetrics.io/docs/usage/startup/), and in particular the section on waiting for your machine to connect to its network.