configure readthedocs with ipython

.readthedocs.yml

@@ -0,0 +1,23 @@
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  configuration: docs/conf.py
+
+# Optionally build your docs in additional formats such as PDF
+formats:
+  - pdf
+
+# Optionally set the version of Python and requirements required to build your docs
+python:
+  version: 3.7
+  install:
+    - method: pip
+      path: .
+      extra_requirements:
+        - docs
+  system_packages: true

setup.py

@@ -9,7 +9,7 @@
 
 extras_require = {
     "dev": ["coverage", "flake8", "pytest >= 4.6", "pytest-cov", "sphinx"],
-    "docs": ["sphinx"],
+    "docs": ["sphinx", "ipython"],
 }
 
 version = ""