Failed to create static_assets using __init__.py in the project root

[klam00]

(Describe the issue here)
init.py

from skygear import static_assets
from skygear.utils.assets import directory_assets

@static_assets('/dev')
def deploy_to_skygear():
    return directory_assets('dist')

This file was in the project root.
When I git push to MYAPPNAME.skygear.io, static assets not getting created.

• Skygear Server Date/Version:
• Application Platform:
• Is this a regression?
• Attached logs, screenshots

Expected Results

Actual Results

Steps to reproduce

1. put this file in the project root, assume your 'dist' folder is not empty
2. git push $MYAPPSKYGEAR $BRANCH:master
3. go to 'http://MYAPPSKYGEAR.skygear.io/static'