Option '--start-server' is useless as it is implied by option '--background'

Closes: #17

Author: ghusta

Dockerfile

@@ -10,4 +10,4 @@ EXPOSE 25
 VOLUME ["/var/mail"]
 
 # Start the STMP server without a GUI (background)
-CMD java -jar /opt/fakeSMTP.jar --start-server --background --port 25 --output-dir /var/mail
+CMD java -jar /opt/fakeSMTP.jar --background --port 25 --output-dir /var/mail