Added function to check permissions on specific chat.

The checkChatPermission function checks if a use is allowed to perform an action in a chat

main.py

@@ -65,6 +65,20 @@ def checkUserPermission(token, permission):
             return False, "Token is expired"
     else:
         return False, "Token doesn't exist"
+    
+def checkChatPermission(token, chatId, permission):
+    a, userId = checkUserPermission(token, True)
+    if (a == True):
+        # Get the chat from the chatId
+        returnedChat = chatCollection.find_one({'_id': ObjectId(chatId)})
+        # Convert chatId into string
+        returnedChat['_id'] = str(returnedChat['_id'])
+        if permission in returnedChat['permissions']:
+            return True, userId
+        else:
+            return False, "Incorrect permissions"
+    else:
+        return False, "Invalid Token"
 
 # Chat Details Endpoint:
 # Get or change details about a chat using the chatId