Added default (testing) values for repo

lib/SugarTrail.pm

 our $VERSION = '0.1';
 
 my $r = SugarTrail::Repo->new(
-    root    => config->{repo_root},
-    vcs     => config->{repo_vcs}
+    root    => config->{repo_root}  // "t/data/strepo",
+    vcs     => config->{repo_vcs}   // "git"
 );