add build mechanism for nng

server/server.Dockerfile

@@ -1,10 +1,11 @@
+ARG GAME_DIR
 FROM elan:latest
 
 WORKDIR /
 
 # Copy lean files
 COPY leanserver ./leanserver
-COPY testgame ./testgame
+COPY $GAME_DIR ./$GAME_DIR
 # TODO: make `testgame` a build argument
 
 WORKDIR /leanserver
@@ -12,4 +13,3 @@ RUN rm -f ./build/bin/gameserver
 RUN lake build
 
 WORKDIR /leanserver/build/bin/
-CMD ["./gameserver", "--server", "testgame", "TestGame", "TestGame"]