docs(mac): Installing kernel extensions using scripts (#1455)

docs/Kernel extensions.md

@@ -0,0 +1,30 @@
+# Kernel extensions
+
+Installing macOS kernel extensions with `electron-builder` can be done using scripts.
+
+First, in `package.json`, make sure you're building a package (.pkg) and not the default .dmg:
+
+```json
+"mac": { 
+	"target": "pkg"
+}
+```
+
+Place your script and the kernel extensions in `build/pkg-scripts`, or [define a custom directory](/~https://github.com/electron-userland/electron-builder/wiki/Options#PkgOptions-scripts). Note that the script **must** be called either `preinstall` or `postinstall`.  Remember to use ` #!/bin/sh` as the first line in your script. Also, your script must be executable (`chmod +x <filename>`).
+
+An example script:
+```sh
+#!/bin/sh
+
+echo "Unloading and uninstalling old extensions..."
+# unload old extensions
+sudo kextunload /Library/Extensions/myExt.kext
+
+# delete old extensions
+sudo rm -rf /Library/Extensions/myExtension.kext
+
+# install new extensions
+echo "Installing and loading new extensions..."
+sudo cp -R myExt.kext /Library/Extensions/myExt.kext
+sudo kextload /Library/Extensions/myExt.kext/
+```