add documentation

README.md

@@ -110,7 +110,7 @@ These options can be configured by setting environment variables using `-e KEY="
 | `WG_CONFIG_PORT`| `51820` | `12345` | The UDP port used on [Home Assistent Plugin](https://github.com/adriy-be/homeassistant-addons-jdeath/tree/main/wgeasy)
 | `WG_MTU` | `null` | `1420` | The MTU the clients will use. Server uses default WG MTU. |
 | `WG_PERSISTENT_KEEPALIVE` | `0` | `25` | Value in seconds to keep the "connection" open. If this value is 0, then connections won't be kept alive. |
-| `WG_DEFAULT_ADDRESS` | `10.8.0.x` | `10.6.0.x` | Clients IP address range. |
+| `WG_DEFAULT_ADDRESS` | `10.8.0.x` | `10.6.0.x` | Clients IP address range. Subnet mask is auto determinated by range (ex: 10.8.0.x/**24**,  10.8.x.x/**16** or 10.x.x.x/**8**) |
 | `WG_DEFAULT_DNS` | `1.1.1.1` | `8.8.8.8, 8.8.4.4` | DNS server clients will use. If set to blank value, clients will not use any DNS. |
 | `WG_ALLOWED_IPS` | `0.0.0.0/0, ::/0` | `192.168.15.0/24, 10.0.1.0/24` | Allowed IPs clients will use. |
 | `WG_PRE_UP` | `...` | - | See [config.js](https://github.com/wg-easy/wg-easy/blob/master/src/config.js#L19) for the default value. |