You're using Capistrano 3, but the project you're using was probably set up for Capistrano 2. Version 3 was a complete rewrite and requires a fair amount of configuration updates to work.
Assuming you have the correct 2.x version of Capistrano in your project's Gemfile
, you should be using bundle exec cap
(to use your project's version) instead of just cap
(which will use the globally-installed 3.x version).
There is an upgrade guide available, though it's not terribly in depth.