fix: typo

Author: chriswblake

src/app.py

@@ -59,7 +59,7 @@ def signup_for_activity(activity_name: str, email: str):
     if activity_name not in activities:
         raise HTTPException(status_code=404, detail="Activity not found")
 
-    # Get the specificy activity
+    # Get the specific activity
     activity = activities[activity_name]
 
     # Add student