docs(readme): add CLI registration

README.md

@@ -63,7 +63,28 @@ This will hopefully be fixed soon.
 [ssl-full]:https://developers.cloudflare.com/ssl/origin-configuration/ssl-modes/full
 [caching-levels]:https://developers.cloudflare.com/cache/how-to/set-caching-levels
 
-## Register a Domain
+## Register
+
+### CLI (*recommended*)
+1. Install the CLI using this command:
+
+```
+npm install @open-domains/cli -g
+```
+
+2. Login to the CLI:
+
+```
+open-domains login
+```
+
+3. Register a domain and follow the steps:
+
+```
+open-domains register
+```
+
+### Manual
 1. **Star** and **[Fork](https://github.com/open-domains/register/fork)** this repository.
 2. Add a new file called `example.domain.json` in the `/domains` folder to register `example` subdomain.
 3. Edit the file (below is just an **example**, provide a **valid** JSON file with your needs, the format is very strict.