def initialize(user:, host:, path:)
      super(scheme: 'git-alt', user: user, host: host, path: path)
    end
Create a new GitAltURI object

@example
uri = Git::GitAltURI.new(user: 'james', host: 'github.com', path: 'james/ruby-git')
uri.to_s #=> 'james@github.com/james/ruby-git'

@param user [String, nil] the user from the URL or nil
@param host [String] the host from the URL
@param path [String] the path from the URL