change sheet content to path

content will be created as tmp dir/file
and controled/passed by git to remote filesystem AWS S3
wrap table javascript and render in the view

also create fake data in controller and
pass it in javascript by erb

next, data will come from S3
use carrierwave_direct to upload file

generally, upload is success
yet, when file size is small,
it will only create new hashed dir and no file is uploaded
add upload page and routes

can redirect with format params received from aws s3
but still can't write it into db
something wrong with mount_uploader and update_attribute
1. there is no method 'update_attribute' for uploader
2. direct update sheet attribute with success returened,
    yet, database is not writed
destory uploaded aws s3 object

still can't figure out how to attach loaded file key to mounted column.
save the key to path column and override it.
path is going to be used like this anyway.

destroy the uploaded file by aws-sdk
depended on the config attached on the uploader
hide aws key into env