docs: add requirements for documentation

1️⃣  fix docs failing due to custom extension

Author: AsifArmanRahman

.readthedocs.yaml

@@ -0,0 +1,32 @@
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Set the version of Python and other tools you might need
+build:
+    os: ubuntu-22.04
+    tools:
+        python: "3.9"
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+   configuration: docs/conf.py
+
+# If using Sphinx, optionally build your docs in additional formats such as PDF
+formats:
+    - pdf
+    - epub
+
+# Optionally declare the Python requirements required to build your docs
+python:
+    install:
+        - method: pip
+          path: .
+          extra_requirements:
+              - docs
+
+        - method: pip
+          path: .

pyproject.toml

@@ -86,10 +86,24 @@ dependencies = [
 	'six>=1.16.0',
 ]
 
+
+[project.optional-dependencies]
+
+docs = [
+	'Sphinx>=5.0.2',
+	'sphinx-rtd-theme>=1.0.0',
+	'sphinx_design>=0.2.0',
+]
+
+
 [project.urls]
 
 # Here is the URL where you can find the code, in this case on GitHub.
 Source = 'https://github.com/AsifArmanRahman/firebase-rest-api'
 
+# Here is the URL where you can find the documentation of the library, in this case on Read the Docs.
+Documentation = 'https://firebase-rest-api.readthedocs.io/'
+
+
 [tool.flit.module]
 name = 'firebase'