docs: Example of how to allow a graceful reload (#1481)

[skip ci]

README.md

@@ -2,7 +2,7 @@
 
 # nodemon
 
-nodemon is a tool that helps develop node.js based applications by automatically restarting the node application when file changes in the directory are detected. 
+nodemon is a tool that helps develop node.js based applications by automatically restarting the node application when file changes in the directory are detected.
 
 nodemon does **not** require *any* additional changes to your code or method of development. nodemon is a replacement wrapper for `node`, to use `nodemon` replace the word `node` on the command line when executing your script.
 
@@ -251,6 +251,38 @@ nodemon --delay 2.5
 }
 ```
 
+## Gracefully reloading down your script
+
+It is possible to have nodemon send any signal that you specify to your application.
+
+```bash
+nodemon --signal SIGHUP server.js
+```
+
+Your application can handle the signal as follows.
+
+```js
+process.once("SIGHUP", function () {
+  reloadSomeConfiguration();
+})
+```
+
+Please note that nodemon will send this signal to every process in the process tree.
+
+If you are using `cluster`, then each workers (as well as the master) will receive the signal. If you wish to terminate all workers on receiving a `SIGHUP`, a common pattern is to catch the `SIGHUP` in the master, and forward `SIGTERM` to all workers, while ensuring that all workers ignore `SIGHUP`.
+
+```js
+if (cluster.isMaster) {
+  process.on("SIGHUP", function () {
+    for (const worker of Object.values(cluster.workers)) {
+      worker.process.kill("SIGTERM");
+    }
+  });
+} else {
+  process.on("SIGHUP", function() {})
+}
+```
+
 ## Controlling shutdown of your script
 
 nodemon sends a kill signal to your application when it sees a file update. If you need to clean up on shutdown inside your script you can capture the kill signal and handle it yourself.