fix: handle nil DocsHandler and add DOCS env var

deploy/base/config.env

@@ -38,3 +38,6 @@ VAULT_URL=http://vault.vault.svc.cluster.local:8200/v1
 
 # Logging
 LOG_LEVEL=info
+
+# Docs
+DOCS=/docs

services/gateway/server/server_http.go

@@ -15,7 +15,9 @@ import (
 func StartHTTP(ctx context.Context, port string) {
 	mux := httptrace.NewServeMux()
 
-	mux.Handle("/docs/", http.StripPrefix("/docs", handlers.DocsHandler()))
+	if docsHandler := handlers.DocsHandler(); docsHandler != nil {
+		mux.Handle("/docs/", http.StripPrefix("/docs", docsHandler))
+	}
 
 	mux.HandleFunc("/session", httphandlers.PanicHandler(handlers.SecureSessionWebsocketHandler))
 	mux.HandleFunc("/secret_mobile", httphandlers.PanicHandler(handlers.InsecureSessionWebsocketHandler))