doc: add link to config on readme

Author: cameri

README.md

@@ -116,6 +116,8 @@ You can change the default folder by setting the `NOSTR_CONFIG_DIR` environment
 Run nostr-ts-relay using one of the quick-start guides at least once and `~/.nostr/settings.json` will be created.
 Any changes made to the settings file will be read on the next start.
 
+See [CONFIGURATION.md](CONFIGURATION.md) for a detailed explanation of each environment variable and setting.
+
 ## Dev Channel
 
 For development discussions, please use the [Nostr Typescript Relay Dev Channel](https://t.me/nostr_ts_relay).