Define and update default_environment to use rbenv over capistrano

[tk0miya]

currently, run(), capture() and sudo() do not use ruby binary installed from rbenv.
so many people defines :default_environment (RBENV_ROOT and PATH) manually.

this fix changes that the remote-executions use rbenv by default.

[yyuu]

Thanks for PR :)

I understood that you're requesting to load rbenv into your shell. But I cannot agree to set default_environment in capistrano-rbenv since modifying some kind of global variables in 3rd party plugin may corrupt interoperability of plugins. I think that those global variables should be set by users explicitly in their recipes.

Now I'm working for same issue by another approach, and will show you in few days.

[tk0miya]

Thank you for comment.

I thought :default_environment is good way for switching ruby environment seemlessly.
but, your comment is correct. updating :default_environment is a little corrupt way.

I'd known it, and added :rbenv_define_default_environment to avoid it.

Now I'm working for same issue by another approach, and will show you in few days.

I'm looking forward to see your fix :-)

Thanks.

[yyuu]

Sorry to be late. I decided to merge this request.

As of writing previous comment, I didn't like capistrano-rbenv to depend on non-standard recipes of capistrano even if it was capistrano-ext. But I changed my mind because your hack seems much simpler than mine, and also it just worked.

I thought that initializing :rbenv_path without capturing remote may solve this situation, and created my workaround as 5b61b3b. With that patch, if we'd like to use :rbenv_path in :default_environment, we have to set :rbenv_expand_path as false before capistrano/ext/multistage has been required. It is not so quite simple and hard to understand.

Thanks so much for comments and patches 👍

[tk0miya]

Thank you for merging!