code: function(str) {
      var path = require('path');
      var name = path.basename(str, path.extname(str));
      var re = /(\d{4})-(\d{2})-(\d{2})-(.+)/;
      // $1 = yyyy, $2 = mm, $3 = dd, $4 = basename
      return name.replace(re, '$4');
    }
docs: For task assemble:filename_replacement