Create todo.md

Mazu is on the road!!
Update todo.md

issue: review comment blocks, see if it is easy to understand. assigned to kunyuchen
Update todo.md

fixed type settings for checkboxes
add some todo tasks
fix format of todo.md
fix format of todo.md
Update todo.md

fixed type settings.
Update todo.md

fixed type settings.
Create doc.md
renamed doc/ to docs/
change model name
add fields into samples/forms.py
#20 remove brokers app
Merge branch 'develop' of https://github.com/PwnDoRa/mazu into improve-samples-app
fix feature: sample upload