DOC: Fixups for rtd
1. Added master_doc
2. Added badge to the README
MODIFY
README.md
README.md
# pangeo-forge
![CI](https://github.com/pangeo-forge/pangeo-forge/workflows/CI/badge.svg)
+[![Documentation Status](https://readthedocs.org/projects/pangeo-forge/badge/?version=latest)](https://pangeo-forge.readthedocs.io/en/latest/?badge=latest)

MODIFY
docs/source/conf.py
docs/source/conf.py
@@ -15,7 +15,7 @@ extensions = [
templates_path = ["_templates"]
exclude_patterns = []
-
+master_doc = "index"
# -- Options for HTML output -------------------------------------------------

DOC: Fixups for rtd

1. Added master_doc
2. Added badge to the README