feat: added docs to website (#186)

* feat(docs): self-hosting s3 minio guide

* feat(docs): self-hosting introduction guide

* fix: build error

* refactor: use kan over kan.bn

---------

Co-authored-by: Henry <henry_ball@hotmail.co.uk>

apps/docs/guides/self-hosting/introduction.mdx

@@ -0,0 +1,140 @@
+---
+title: "Introduction"
+description: "Overview and quick start to run Kan on your own infrastructure using Docker Compose."
+mode: "wide"
+tag: "NEW"
+---
+
+This guide introduces how to self-host Kan. It starts with the minimal Docker Compose setup (web + PostgreSQL) and points you to optional features like email and S3-based file storage.
+
+## What you’ll set up
+
+<CardGroup cols={2}>
+  <Card title="Kan" icon="globe" color="#0284c7" horizontal>
+    Next.js application served on port 3000.
+  </Card>
+  <Card title="PostgreSQL 15" icon="database" color="#65a30d" horizontal>
+    Primary database for Kan data.
+  </Card>
+</CardGroup>
+
+<Note>
+  For file uploads (avatars), OAuth, and other advanced options, see the
+  Environment Variables section in the README and the dedicated [S3
+  guide](/guides/self-hosting/s3). The [full
+  compose](https://github.com/kanbn/kan/blob/main/docker-compose.yml) in the
+  repo includes a richer configuration via <code>.env</code>.
+</Note>
+
+## Prerequisites
+
+- Docker and Docker Compose
+- A long random string for <code>BETTER_AUTH_SECRET</code> (32+ chars)
+
+## Quick start
+
+<Steps>
+  <Step title="Create a docker-compose.yml">
+    Paste the following minimal configuration into a new <code>docker-compose.yml</code> file:
+
+    ```yaml
+    services:
+      web:
+        image: ghcr.io/kanbn/kan:latest
+        container_name: kan-web
+        ports:
+          - "3000:3000"
+        networks:
+          - kan-network
+        environment:
+          NEXT_PUBLIC_BASE_URL: http://localhost:3000
+          BETTER_AUTH_SECRET: your_auth_secret
+          POSTGRES_URL: postgresql://kan:your_postgres_password@postgres:5432/kan_db
+          NEXT_PUBLIC_ALLOW_CREDENTIALS: true
+        depends_on:
+          - postgres
+        restart: unless-stopped
+
+      postgres:
+        image: postgres:15
+        container_name: kan-db
+        environment:
+          POSTGRES_DB: kan_db
+          POSTGRES_USER: kan
+          POSTGRES_PASSWORD: your_postgres_password
+        ports:
+          - 5432:5432
+        volumes:
+          - kan_postgres_data:/var/lib/postgresql/data
+        restart: unless-stopped
+        networks:
+          - kan-network
+
+    networks:
+      kan-network:
+
+    volumes:
+      kan_postgres_data:
+    ```
+
+    <Tip>
+      The example above is intentionally minimal. The repository provides a more feature-complete compose file at [docker-compose.yml](https://github.com/kanbn/kan/blob/main/docker-compose.yml) if you want environment-based configuration, OAuth, S3, and more.
+    </Tip>
+
+  </Step>
+
+  <Step title="Start the stack">
+    Bring everything up in detached mode:
+
+    ```bash
+    docker compose up -d
+    ```
+
+    Once started, open [http://localhost:3000](http://localhost:3000).
+
+  </Step>
+
+  <Step title="Manage the containers">
+    Useful commands while developing or testing:
+
+    - Stop the containers: <code>docker compose down</code>
+    - View logs: <code>docker compose logs -f</code>
+    - Restart: <code>docker compose restart</code>
+
+  </Step>
+
+  <Step title="Configure environment (optional)">
+    For a production-like setup and more features (email, OAuth, file uploads, etc.), create a <code>.env</code> file and set the relevant variables shown in the README’s Environment Variables section.
+
+    <Accordion title="Common variables">
+      ```bash
+      # Required
+      NEXT_PUBLIC_BASE_URL=http://localhost:3000
+      BETTER_AUTH_SECRET=replace_with_long_random_string
+      POSTGRES_URL=postgresql://kan:your_postgres_password@postgres:5432/kan_db
+
+      # Optional: Email
+      EMAIL_FROM="Kan <hello@mail.kan.bn>"
+      SMTP_HOST=smtp.resend.com
+      SMTP_PORT=465
+      SMTP_USER=resend
+      SMTP_PASSWORD=re_xxxx
+      SMTP_SECURE=true
+
+      # Optional: Auth toggles
+      NEXT_PUBLIC_ALLOW_CREDENTIALS=true
+      NEXT_PUBLIC_DISABLE_SIGN_UP=false
+      ```
+
+      <Note type="warning">
+        If you plan to enable file uploads (avatars, etc.), you’ll also need S3 variables (<code>S3_ENDPOINT</code>, <code>S3_ACCESS_KEY_ID</code>, <code>S3_SECRET_ACCESS_KEY</code>, <code>NEXT_PUBLIC_STORAGE_URL</code>, <code>NEXT_PUBLIC_STORAGE_DOMAIN</code>, …). See the S3 guide linked at the top.
+      </Note>
+    </Accordion>
+
+  </Step>
+</Steps>
+
+## Reference
+
+- [GitHub README](https://github.com/kanbn/kan/blob/main/README.md#self-hosting-)
+- [GitHub docker-compose.yml](https://github.com/kanbn/kan/blob/main/docker-compose.yml)