I'm using a gem refile I stumbled, so I will leave it as a memorandum.
ruby 2.5.7 Rails 22.214.171.124 OS: macOS Catalina
tmp/uploads/store Although it is under this, like the character tmp = temporary, This is a temporary storage location.
If you want to save under public / uploads Create refile.rb under config / initializers.
Refile.backends['store'] = Refile::Backend::FileSystem.new('public/uploads/')
If you do this, you can save it under public / uploads.