mitchellh/vagrant — pull request #4246 by synth3tk (2014-07-24 16:03:58+00:00)
Title: Fix 'vagrant up' command in Docker docs

Without the `--provider=docker` argument, running `vagrant up` causes an error:

There are errors in the configuration of this machine. Please fix
the following errors and try again:

vm:
* A box must be specified.