Docs updates (#329)

* Add doctoc

* Document schemes argument

.pre-commit-config.yaml

@@ -16,5 +16,11 @@ repos:
 - repo: https://github.com/pre-commit/mirrors-mypy
   rev: v1.8.0
   hooks:
-  - id: mypy
-    additional_dependencies: ["marshmallow>=3,<4"]
+    - id: mypy
+      additional_dependencies: ["marshmallow>=3,<4"]
+- repo: https://github.com/thlorenz/doctoc.git
+  rev: v2.2.0
+  hooks:
+    - id: doctoc
+      name: Add TOC for Markdown and RST files
+      files: README\.md

README.md

@@ -10,26 +10,32 @@ It allows you to store configuration separate from your code, as per
 
 ## Contents
 
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+
 - [Features](#features)
 - [Install](#install)
 - [Basic usage](#basic-usage)
 - [Supported types](#supported-types)
-- [Reading .env files](#reading-env-files)
+- [Reading `.env` files](#reading-env-files)
   - [Reading a specific file](#reading-a-specific-file)
 - [Handling prefixes](#handling-prefixes)
 - [Variable expansion](#variable-expansion)
 - [Validation](#validation)
 - [Deferred validation](#deferred-validation)
+- [URL schemes](#url-schemes)
 - [Serialization](#serialization)
 - [Defining custom parser behavior](#defining-custom-parser-behavior)
 - [Usage with Flask](#usage-with-flask)
 - [Usage with Django](#usage-with-django)
-- [Why...?](#why)
+- [Why\...?](#why%5C)
   - [Why envvars?](#why-envvars)
-  - [Why not os.environ?](#why-not-osenviron)
+  - [Why not `os.environ`?](#why-not-osenviron)
   - [Why another library?](#why-another-library)
 - [License](#license)
 
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
 ## Features
 
 - Type-casting
@@ -252,6 +258,16 @@ env.seal()
 
 `env.seal()` validates all parsed variables and prevents further parsing (calling a parser method will raise an error).
 
+## URL schemes
+
+`env.url()` supports non-standard URL schemes via the `schemes` argument.
+
+```python
+REDIS_URL = env.url(
+    "REDIS_URL", "redis://redis:6379", schemes=["redis"], require_tld=False
+)
+```
+
 ## Serialization
 
 ```python