chore: update readme

Author: Zekfad

ReadMe.md

@@ -1,32 +1,38 @@
 # dev-mirror
 
-Simple mirror (proxy) server for private APIs testing which will help you
-to keep your private credentials out of build artifacts.
+Simple mirror (proxy) server for private APIs testing.
+It will help you to keep private credentials out of build artifacts.
 
 ## Features
 
 * Target server authentication
 * Local server authentication
-* Spoofing referer
+* Spoofing referrer
 * CORS bypass
 
 ## Usage
 
-Use environmental variables or `.env`:
-```.env
+Use environmental variables or `.env` file in working directory:
+```dotenv
+# Remote HTTP(S) server
 SERVER_SCHEME = https
 SERVER_HOST = example.com
 SERVER_PORT = 443
-# HTTP Basic auth
+# Remote server HTTP Basic auth
 SERVER_USERNAME = user
 SERVER_PASSWORD = passw0rd
+# Local HTTP server
 LOCAL_BIND_IP = 127.0.0.1
 LOCAL_PORT = 8080
-# HTTP Basic auth
+# Local server HTTP Basic auth
 LOCAL_USERNAME = user
 LOCAL_PASSWORD = passw0rd
 ```
 
-Keep in mind, that if you have local server authentication without target
-server authentication you wont be able to authenticate.
+Keep in mind, that if you have local server authentication, you wont be able
+to send authentication details to remote server though the mirror.
 
+That means, that configuration where remote server requires authentication and
+mirror has no remote credentials, but has local authentication is invalid.
+To fix this add remote credentials (recommended), or disable local
+authentication.