add(taskwarrior): pull implementation for new tasks

This implements the pull functionality for new tasks, which are not yet
in the local taskwarrior instance created. WIP for #3.

cmd/gitw/main.go

@@ -23,11 +23,11 @@ func main() {
 	}
 	project := gitw.NewProject(server, repository)
 
-	if err = project.Fetch(); err != nil {
+	fmt.Printf("Pulling changes from %s\n", repository.Full_name)
+	if err = project.Pull(); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(-1)
 	}
-	fmt.Printf("%#v\n", project)
 
 	// NOTE: this can be used to add / modify tasks
 	// var update_tasks []taskwarrior.Task