add robin v2 to the arena

app.py

@@ -141,6 +141,7 @@ AVAILABLE_MODELS = {
     "minotaur-13b-fixed": ("sjnkstd3e40ojj", prompt_roleplay),
     "wizardlm-13b": ("k0chcxsgukov8x", prompt_instruct),
     "selfee-13b": ("50rnvxln9bmf4c", prompt_instruct),
+    "robin-v2-13b": ("4cw4vwzzhsl5pq", prompt_instruct),
 }
 
 OAAIC_MODELS = [