feat(connect): add CONNECT_TOKEN env var

.web/docs/guide/install/docker.md

@@ -37,14 +37,27 @@ This command will pull and run the latest Gate image.
 
 ### Mounting a config file and Minekube Connect token
 
+#### Using an environment variable for the token
+
+```sh{3} console
+docker run -it --rm \
+  -v PATH-TO-CONFIG/config.yml:/config.yml \
+  -e CONNECT_TOKEN=YOUR-TOKEN \
+  ghcr.io/minekube/gate:latest
+```
+
+**Note:** The `CONNECT_TOKEN` environment variable takes precedence over the `connect.json` file, so if both are provided, the token from the environment variable will be used instead.
+
+#### Using a volume for the token
+
 ```sh{3} console
 docker run -it --rm \
   -v PATH-TO-CONFIG/config.yml:/config.yml \
   -v PATH-TO-CONFIG/connect.json:/connect.json \
   ghcr.io/minekube/gate:latest
 ```
 
-A [Minekube Connect](https://connect.minekube.com/) token json file can be automatically generated by running Gate with `connect.enable: true` in the config.
+A [Minekube Connect](https://connect.minekube.com/) token json file can be automatically generated by running Gate with `connect.enable: true` in the config. 
 
 ```json connect.json
 {"token":"YOUR-TOKEN"}

pkg/util/connectutil/config/auth.go

@@ -12,8 +12,13 @@ import (
 
 const tokenFilename = "connect.json"
 
-// load auth token from file or generates it
+// load auth token from env, file or generates it
 func loadToken(filename string) (string, error) {
+	// env always takes precedence
+	if token := os.Getenv("CONNECT_TOKEN"); token != "" {
+		return token, nil
+	}
+
 	// If the file doesn't exist, create it, or append to the file
 	f, err := os.OpenFile(filename, os.O_RDWR|os.O_CREATE, 0644)
 	if err != nil {