Add documentation for Vault

Author: inf1nite-lo0p

docs/modules/vault.md

@@ -0,0 +1,37 @@
+# Vault Module
+
+[Vault](https://www.vaultproject.io/) by HashiCorp is a tool for securely accessing secrets such as API keys, passwords, or certificates. This module allows you to run and initialize a Vault container for integration tests.
+
+## Install
+
+```bash
+npm install @testcontainers/vault --save-dev
+```
+
+## Examples
+
+Start a Vault container with a root token:
+
+<!--codeinclude-->
+
+[Start and perform read/write with node-vault:](../../packages/modules/vault/src/vault-container.test.ts) inside_block:readWrite
+
+<!--/codeinclude-->
+
+Initialize secret engines and keys using Vault CLI:
+
+<!--codeinclude-->
+
+[Run Vault CLI init commands at startup:](../../packages/modules/vault/src/vault-container.test.ts) inside_block:initCommands
+
+<!--/codeinclude-->
+
+## Why use Vault in integration tests?
+
+With the growing adoption of Vault in modern infrastructure, testing components that depend on Vault for secret resolution or encryption can be complex. This module allows:
+
+- Starting a local Vault instance during test runs
+- Seeding secrets or enabling engines with Vault CLI
+- Validating app behavior with secured data access
+
+Use this module to test Vault-backed workflows without the need for pre-provisioned Vault infrastructure.

mkdocs.yml

@@ -84,5 +84,6 @@ nav:
       - Selenium: modules/selenium.md
       - ToxiProxy: modules/toxiproxy.md
       - Valkey: modules/valkey.md
+      - Vault: modules/vault.md
       - Weaviate: modules/weaviate.md
   - Configuration: configuration.md