Update readme.md

Author: macbre

readme.md

@@ -12,7 +12,7 @@ docker pull macbre/nginx-brotli:1.17.9-1
 
 # SSL Grade A+ handling
 
-Please refer to [Mozilla's SSL Configuration Generator](https://ssl-config.mozilla.org/). This image has `https://ssl-config.mozilla.org/ffdhe2048.txt` fetched and stored in `/etc/ssl/dhparam.pem`:
+Please refer to [Mozilla's SSL Configuration Generator](https://ssl-config.mozilla.org/). This image has `https://ssl-config.mozilla.org/ffdhe2048.txt` DH parameters for DHE ciphers fetched and stored in `/etc/ssl/dhparam.pem`:
 
 ```
     ssl_dhparam /etc/ssl/dhparam.pem;