docs: add some information about the ssh key related flags for configuration

Author: shreddedbacon

docs/config.md

@@ -31,6 +31,15 @@ If you want to add a different Lagoon context to use, then you can use the CLI c
 ```bash
 lagoon config add --lagoon example
 ```
+
+It is also possible to set an SSH key or public key itendity file to use when adding (or updating) a context. 
+
+The flag `--publickey-identitfyfile /path/to/key.pub` can be used to tell the CLI which public key identity in your SSH agent should be used.
+
+The flag `--ssh-key /path/to/key` can be used to tell the CLI which SSH private key should be used.
+
+For troubleshooting, see [troubleshooting SSH keys](./config.md#ssh-keys)
+
 ## Example
 ```bash
 lagoon config add --lagoon amazeeio \