Issue with Capistrano calling shell script that depends on Ruby

Chruby works great, but I'm having an issue when trying to use Ruby in a shell script that Capistrano calls:

```bash
#!/usr/bin/env sh
# ...snip...
ruby --something
# ...snip...
```

It runs in a Capistrano task like this:

```ruby
task :that_calls_shell_script do
    on roles(:app) do
      within release_path do
          execute "path/to/shell/script"
      end
    end
  end
```

The problem is, if I understand correctly, that Capistrano Chruby only seems to call Chruby through `chruby-exec`, which is nice and self-contained, but a problem when you need the Chruby environment there for other purposes.

Is there some kind of workaround?