How to run ruby ​​gems through capistrano?

Question

ruby

ubuntu server target machine. capistrano works. I can do something like:

desc 'Релоад nginx'
  task :reload do
    on roles :all do
      sudo :service, :nginx, :reload
    end
  end

but for some reason I can’t run, for example, rake, backup
For example, this doesn’t work:

desc 'Выполнение бекапа'
  task :perform do
    on roles :all do
       execute :backup, "perform --trigger mybackup"
    end
  end

linux gives an error command backup not found, although if you connect to a server and manually run from any folder, the backup will work.
capistrano produces the following log:

INFO [9a6dd502] Running /usr/bin/env backup perform --trigger mybackup as [email protected]

I suspect that the /usr/bin/env prefix is ​​the problem, but it prepends it to every command and the other commands work.