Given that we have a simple CRUD app with Paperclip

• Album has_attached_file :cover_art
• Album has_many :images
• Image has_attached_file :file

We can upgrade to attache while keeping all the S3 files intact and in place.

• add attache_rails to Gemfile
• add json columns to tables
• populate json columns with existing paperclip urls & metadata
• use has_one_attache and/or has_many_attaches in model
• use *_url and/or *_urls helper methods to render image_tag instead
• update strong params

After the upgrade is applied (and db:migrate is done) then we an look to remove paperclip gem, aws gem and S3 config

We can also look to enable attache js to make browser upload faster (directly to attache, instead of uploading the files to your rails app)