Merge pull request #13 from pymc-devs/readme_attrib

Added contributions to README

README.md

@@ -1,4 +1,13 @@
-PyMC4
-=====
+# PyMC4
 
-Pre-release development of high-level probabilistic programming interface for TensorFlow.  Please contribute or participate [on github](https://github.com/pymc-devs/pymc4).
+Pre-release development of high-level probabilistic programming interface for TensorFlow.  Please contribute or participate [on github](https://github.com/pymc-devs/pymc4).
+
+## Contributors
+
+For a full list of code contributors based on code checkin activity, see the [GitHub contributor page](https://github.com/pymc-devs/pymc4/graphs/contributors).
+
+As PyMC4 builds upon TensorFlow, particularly the TensorFlow Probability and Edward2 modules, its design is heavily influenced by innovations introduced in these packages. In particular, early development was partially derived from a [prototype](https://colab.research.google.com/drive/15Vth0taPoTL3JmL_tw1J2IYM22ufP_1m#scrollTo=-Kcs3_9TL4bh) written by Josh Safyan.
+
+## License
+
+[Apache License, Version 2.0](https://github.com/pymc-devs/pymc4/blob/master/LICENSE)