Prevent games from starting with only one player

Disabled with DEV_MODE=TRUE env var
Fixes #9

src/controller/client.py

@@ -1,5 +1,6 @@
 """Handles communication between one WebSocket tunnel and the game"""
 
+import os
 from typing import Callable, Any, TYPE_CHECKING, Awaitable
 from pydantic import ValidationError
 
@@ -165,10 +166,12 @@ class ClientController:
         but the game isn't yet started"""
         if message.type == "ready":
             self.player.ready = bool(message.data)
+            await self.player.notify_update()
             if all(p.ready for p in self.game_controller.game.players):
-                await self.game_controller.start_game()
-            else:
-                await self.player.notify_update()
+                if ("DEV_MODE" in os.environ) or len(
+                    self.game_controller.game.players
+                ) > 1:
+                    await self.game_controller.start_game()
 
     @vibe_check(Message)
     async def game_context(self, message: Message) -> None: