endpoint: https://seed-project-v1.appspot.com/api/v1
all json except /images
###users:
POST /users
params: email, password
GET /users/{id}
POST /tokens
params: email, password
set the token to header with X-WALKER-ACCESS-TOKEN
###files:
POST /files
using multipart
params: file, file_type
file_type: 'file|image'
description: if file_type == image, serving_url will be provided, otherwise
download url via: http://storage.googleapis.com/{gcs_path}
##Change logs
POST /images
-> POST /files
###images:
POST /images