Add binder directory to list of dirs

Author: frreiss

README.md

@@ -84,6 +84,7 @@ To run the notebooks on your local machine, follow the following steps:
 * **env.sh**: Script to create a conda environment `pd` capable of running the notebooks and test cases in this project
 * **generate_docs.sh**: Script to build the [API documentation]((https://readthedocs.org/projects/text-extensions-for-pandas/)
 * **api_docs**: Configuration files for `generate_docs.sh`
+* **binder**: Configuration files for [running notebooks on Binder](https://mybinder.org/v2/gh/frreiss/tep-fred/branch-binder?urlpath=lab/tree/notebooks)
 * **config**: Configuration files for `env.sh`.
 * **docs**: Project web site
 * **notebooks**: example notebooks