add Dockerfile

Signed-off-by: Florian Brandes <florian.brandes@posteo.de>

README.md

@@ -11,6 +11,8 @@ This can also for example use `msmtp`. This way scripts can use `sendmail` which
 
 Additionally, we can sign and encrypt the emails with S/MIME certificates, which adds a layer of authentification and security for automated information delivery (think security notifications, logs, etc.)
 
+Please note: This will only forward emails to email addresses specified in `config.ini`, so it is not useful as a general SMTP-relay (like `msmtp`) but only for a predefined email set. This is by design.
+
 For now, this is a proof-of-concept.
 
 
@@ -49,6 +51,17 @@ Note: `build` must be installed. You should use a `venv` for this.
 
 Clone this repo and run `devenv shell`
 
+### docker
+
+
+
+1. Clone this repo
+2. `cp config.example config.ini`
+3. edit `config.ini` as you need it. I'd suggest using `/app/pw` as password file and bild-mounting it.
+4. `docker build -t smtprd-ng:latest .`
+5. `docker run  -p 8025:8025 -v ./config.ini:/app/config.ini -v ./pw:/app/pw --rm -it smtprd-ng:latest`
+
+
 ## Contributing
 
 Contributions are always welcome!