Add Sphinx documentation

.github/workflows/docs.yml

@@ -0,0 +1,14 @@
+name: Documentation Check
+on:
+- pull_request
+
+jobs:
+  sphinx:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v1
+    - uses: josh146/sphinx-action@master
+      with:
+        docs-folder: "docs/"
+        pre-build-command: "apt install -y graphviz && pip3 install . && pip3 install -r docs/requirements.txt"
+        build-command: "sphinx-build -b html . _build -W --keep-going"

.gitignore

@@ -70,6 +70,7 @@ instance/
 
 # Sphinx documentation
 docs/_build/
+docs/api/
 
 # PyBuilder
 target/

.readthedocs.yml

@@ -0,0 +1,14 @@
+version: 2
+
+sphinx:
+  configuration: docs/conf.py
+
+python:
+    version: 3.7
+    install:
+        - requirements: docs/requirements.txt
+        - method: pip
+          path: .
+
+build:
+    image: latest