Update Dockerfile

Dockerfile

@@ -11,4 +11,7 @@ ENV CALENDAR_NAME $CALENDAR_NAME
 ENV USERNAME $USERNAME
 ENV PASSWORD $PASSWORD
 ENV RA_API $RA_API
-ENV RA_USER $RA_USER
+ENV RA_USER $RA_USER
+
+ENTRYPOINT ["sh", "-c"]
+CMD python3 ./app.py "$CALDAV_URL" "$CALENDAR_NAME" "$USERNAME" "$PASSWORD" "$RA_API" "$RA_USER"