Image upload solution

[lulalala]

Currently I am evaluating Carrierwave and Refile.

Carrierwave

• Provide versioning to resize image, which Nginx can serve directly.
• Build-in multi-file upload through the use of serialized column.

  Refile

• Direct upload to S3, which is beneficial for Heroku users.
• Upload ahead of submit.
• CON: Need CDN since images are served via Rack endpoint.

[lulalala]

Carrierwave is chosen at the end. The main reason is that asking the board hoster to setup a CDN can be difficult.

The multi-file upload is not used, because I think a separate images table would allow later extensions.