added debian to build

backend/build.bat

@@ -1 +1,34 @@
-go build -ldflags="-H=windowsgui" -o nsfwapp.exe
+@echo off
+setlocal
+
+echo Baue Windows x64...
+
+set GOOS=windows
+set GOARCH=amd64
+set CGO_ENABLED=1
+
+go build -ldflags="-H=windowsgui" -o nsfwapp.exe
+if errorlevel 1 goto error
+
+echo.
+echo Baue Debian/Linux x64 via WSL...
+
+for /f "delims=" %%i in ('wsl wslpath -a "%CD%"') do set "WSL_CWD=%%i"
+
+wsl --cd "%WSL_CWD%" bash -lc "GOOS=linux GOARCH=amd64 CGO_ENABLED=1 go build -o nsfwapp-linux-amd64"
+if errorlevel 1 goto error
+
+echo.
+echo Build erfolgreich.
+echo Windows: nsfwapp.exe
+echo Debian:  nsfwapp-linux-amd64
+goto end
+
+:error
+echo.
+echo Build fehlgeschlagen.
+exit /b 1
+
+:end
+endlocal
+pause