Better sorting for ls

Task.py

@@ -8,7 +8,8 @@ class Task:
         self.text = text
         self.completion_date = None
         self.creation_date = None
-        self.priority = None
+        # for sorting, lower than all alphabet letters
+        self.priority = "{"
         self.done = False
         self.projects = []
         self.contexts = []

bot.py

@@ -149,7 +149,7 @@ def ls_tasks(arguments, chat_id):
         tasks[i] = (counter, tasks[i])
         counter += 1
 
-    tasks = sorted(tasks, key=lambda tup: tup[1].text)
+    tasks = sorted(tasks, key=lambda tup: tup[1].priority)
 
     # create list of filters
     filters = []