In commit 7980178d194bb21bde2e21858fbc969e4cc7eb3f (#10879) I added a `usable?` class method to `VagrantPlugins::DockerProvider::Provider`. However, commit 34e53a5a4b208edcc3e25c1f0e3aa0ef56e8d8d9 (#10890) incorrectly changed it to an instance method. This rendered it ineffective because it’s called on the class, not an instance. Change it back to a class method. Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Vagrant Core Plugins
These are plugins that ship with Vagrant. Vagrant core uses its own plugin system to power a lot of the core pieces that ship with Vagrant. Each plugin will have its own README which explains its specific role.