Add back colab link

README.md

@@ -13,9 +13,9 @@ PySR uses evolutionary algorithms to search for symbolic expressions which optim
 
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-| **Docs** | **pip** | **conda** | **Stats** |
-|---|---|---|---|
-|[![Documentation](https://github.com/MilesCranmer/PySR/actions/workflows/docs.yml/badge.svg)](https://astroautomata.com/PySR/)|[![PyPI version](https://badge.fury.io/py/pysr.svg)](https://badge.fury.io/py/pysr)|[![Conda Version](https://img.shields.io/conda/vn/conda-forge/pysr.svg)](https://anaconda.org/conda-forge/pysr)|<div align="center">pip: [![Downloads](https://pepy.tech/badge/pysr)](https://badge.fury.io/py/pysr)<br>conda: [![Anaconda-Server Badge](https://anaconda.org/conda-forge/pysr/badges/downloads.svg)](https://anaconda.org/conda-forge/pysr)</div>|
+| **Docs** | **colab** | **pip** | **conda** | **Stats** |
+|---|---|---|---|---|
+|[![Documentation](https://github.com/MilesCranmer/PySR/actions/workflows/docs.yml/badge.svg)](https://astroautomata.com/PySR/)|[![Colab](https://img.shields.io/badge/colab-notebook-yellow)](https://colab.research.google.com/github/MilesCranmer/PySR/blob/master/examples/pysr_demo.ipynb)|[![PyPI version](https://badge.fury.io/py/pysr.svg)](https://badge.fury.io/py/pysr)|[![Conda Version](https://img.shields.io/conda/vn/conda-forge/pysr.svg)](https://anaconda.org/conda-forge/pysr)|<div align="center">pip: [![Downloads](https://pepy.tech/badge/pysr)](https://badge.fury.io/py/pysr)<br>conda: [![Anaconda-Server Badge](https://anaconda.org/conda-forge/pysr/badges/downloads.svg)](https://anaconda.org/conda-forge/pysr)</div>|
 
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