[docs] add more comparison baseline implementation

Author: tswsxk

docs/irt_tutorial.ipynb

@@ -290,7 +290,9 @@
  "\n",
  "[pyirt](https://github.com/17zuoye/pyirt),\n",
  "[bayesian-irt](https://github.com/jamalex/bayesian-irt),\n",
- "[irt_parameter_estimation](https://github.com/pluralsight/irt_parameter_estimation)\n",
+ "[irt_parameter_estimation](https://github.com/pluralsight/irt_parameter_estimation),\n",
+ "[pypsy](https://github.com/inuyasha2012/pypsy),\n",
+ "[vibo](https://github.com/mhw32/variational-item-response-theory-public)\n",
  "and [irt](https://github.com/aimir/irt)\n",
  "are high-stared implementation of IRT in github.\n",
  "We run them on the cdbd dataset and report the result (AUC and MAP is reported) in the following tables,\n",