[CardsAgainstHumanity] Fix for joincah + id match

cah/cah.py

@@ -71,11 +71,18 @@ class CardsAgainstHumanity(BaseCog):
                 return member
         # No member yet - try ID
         memID = "".join(list(filter(str.isdigit, name)))
-        newMem = memberForID(memID, server)
+        newMem = self.memberforid(memID, server)
         if newMem:
             return newMem
         return None
 
+    @staticmethod
+    def memberforid(checkid, server):
+        for member in server.members:
+            if str(member.id) == str(checkid):
+                return member
+        return None
+
     def getreadabletimebetween(self, first, last):
         # A helper function to make a readable string between two times
         timeBetween = int(last - first)