example.py

import csv

with open('tasks.csv', mode='r') as infile:
    reader = csv.reader(infile)
    tasks = [{'task': row[0], 'done': row[1]} for row in reader]

print tasks
incomplete = [task for task in tasks if task['done'] == 'ne']

while incomplete:
    action = raw_input('uredi/dodaj')
    if action == 'uredi':
        for task in incomplete:
            done = raw_input('Je opravilo: %s narejeno?(da/ne)' % task['task'])
            task['done'] = done

    else:
        task = raw_input('Opis taska: ')
        narejeno = raw_input('Narejeno?')
        task_dict = {
            'task': task,
            'done': narejeno
        }
        tasks.append(task_dict)

    incomplete = [task for task in tasks if task['done'] == 'ne']

    nadaljuj = raw_input('Nadaljuj?')
    if nadaljuj != 'da':
        break

with open('tasks.csv', 'w') as csv_file:
    writer = csv.writer(csv_file)
    writer.writerows([[task['task'], task['done']] for task in tasks])