docs: Update README with info on new config option

README.md

@@ -8,12 +8,26 @@ This is a simple CLI you can use to continuously update an A DNS record for a do
 
 ```
     -k, --key <auth-key>     The auth key you need to generate in your Cloudflare profile
-    -c, --cache <cache>      Cache file for previously reported IP address (if skipped the IP will be reported on every execution)
+    -c, --cache <cache>      Cache file for previously reported IP address (if skipped the IP will be reported on every
+                             execution)
+    -f, --config <config>    Your TOML config file containing all the required options (email, auth_key, zone, domain)
+                             which you can use instead of passing the arguments to the command line
     -d, --domain <domain>    The domain for which you want to report the current IP address
     -e, --email <email>      Your Cloudflare login email
     -z, --zone <zone>        The zone in which your domain is (usually that is your base domain name)
 ```
 
+### Config
+
+You Can pass a path to a configuration file (`-f` or `--config`) instead of each option as a command line argument. The configuration should be a [TOML](https://github.com/toml-lang/toml) file and hold the same options. Here's a sample:
+
+```TOML
+email = "example@example.com"
+auth_key = "secretkey"
+domain = "example.example.com"
+zone = "example.com"
+```
+
 ## Cloudflare Setup
 
 You need to do some preparatory work in Cloudflare. Firstly this assumes you're using Cloudflare already to manage the DNS records for your domain.