added icon and link to the docs section

Author: Adez017

docs/Docker/intro.md

@@ -0,0 +1,108 @@
+<div align="center">
+
+# Introduction to Docker
+</div>
+
+Docker is a platform for building, shipping, and running applications in lightweight, portable containers. Containers package an application and its dependencies together, ensuring consistent behavior across development, CI, and production environments.
+
+## Why use Docker
+- Reproducible runtime environments across machines and teams.
+- Faster developer workflows (build once, run anywhere).
+- Resource-efficient compared to full virtual machines.
+- Simplifies dependency management and deployment pipelines.
+
+## Core concepts
+- Image: Immutable, read-only snapshot that contains application code, runtime, libraries, and metadata. Built from a Dockerfile.
+- Container: A running instance of an image; isolated filesystem, network namespace, and process tree.
+- Dockerfile: Declarative text file that defines how to build an image.
+- Registry: A service to store and distribute images (Docker Hub, private registries).
+- Volume: Persistent storage that lives outside container lifecycle.
+- Network: Isolation and connectivity between containers (bridge, host, overlay).
+- Tag: Named pointer to an image version (e.g., myapp:1.0, nginx:latest).
+
+## Key components
+- Docker Engine: The runtime that builds and runs containers.
+- Docker CLI: Command-line interface (docker) to interact with the Engine.
+- Docker Compose: Tool to define and run multi-container applications via YAML.
+- Docker Desktop: Desktop application for macOS/Windows that bundles Engine, CLI, and tools.
+- Registry/Hub: Public or private storage for images.
+
+## Typical workflow
+1. Write a Dockerfile that describes the application image.
+2. Build the image: `docker build -t myapp:latest .`
+3. Run a container: `docker run -d --name myapp -p 8080:80 myapp:latest`
+4. Test and iterate locally.
+5. Push image to a registry: `docker push myregistry/myapp:latest`
+6. Deploy by pulling the image to target hosts or orchestrator.
+
+## Minimal examples
+
+Dockerfile (simple Node.js app):
+```dockerfile
+FROM node:18-alpine
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci --production
+COPY . .
+CMD ["node", "server.js"]
+```
+
+Run an nginx container:
+```bash
+docker run -d --name web -p 80:80 nginx:stable
+```
+
+docker-compose.yml (web + redis):
+```yaml
+version: "3.8"
+services:
+  web:
+    build: .
+    ports:
+      - "8080:80"
+    depends_on:
+      - redis
+  redis:
+    image: redis:7-alpine
+```
+Start: `docker compose up -d`
+
+## Useful commands
+- Build: `docker build -t myapp:tag .`
+- Run: `docker run -d -p 80:80 --name app myapp:tag`
+- List running containers: `docker ps`
+- List images: `docker images`
+- Exec into container: `docker exec -it app /bin/sh`
+- Logs: `docker logs -f app`
+- Remove container/image: `docker rm app`, `docker rmi myapp:tag`
+- Compose: `docker compose up -d`, `docker compose logs -f`
+
+## Best practices
+- Use small base images (alpine, distroless) when possible.
+- Follow multi-stage builds to reduce final image size.
+- Do not store secrets in images; use environment variables, secrets managers, or Docker Secrets.
+- Keep images immutable and versioned with tags.
+- Add a .dockerignore file to speed builds and avoid leaking files.
+- Run processes as non-root inside containers when feasible.
+- Add HEALTHCHECK to images for orchestration health reporting.
+
+## Security considerations
+- Scan images for vulnerabilities regularly.
+- Minimize installed packages and attack surface.
+- Use official or trusted base images.
+- Pin image digests or tags for reproducible deployments.
+- Limit container capabilities and use user namespaces or seccomp profiles.
+
+## Troubleshooting tips
+- If container fails to start: check `docker logs <container>` and `docker inspect <container>`.
+- Network issues: inspect networks (`docker network ls`, `docker network inspect`).
+- Build issues: add `--progress=plain` and check Dockerfile layers; use `docker build --no-cache` to force rebuild.
+
+## Next steps / learning path
+- Install Docker Desktop (Windows/macOS) or Docker Engine (Linux).
+- Learn Dockerfile best practices and multi-stage builds.
+- Learn Docker Compose for multi-container dev environments.
+- Explore orchestration: Kubernetes or Docker Swarm for production-scale deployments.
+- Read the official docs: https://docs.docker.com/
+
+This file should serve as a concise reference for getting started with Docker and as a base to link to more detailed guides (Dockerfile patterns, Compose, security hardening, CI/CD integrations).

docusaurus.config.ts

@@ -107,6 +107,7 @@ const config: Config = {
                    <a href="/docs/GitHub/intro-github" class="nav__icons" > <img src="/icons/github.svg" title="GitHub" alt="GitHub" /> </a>
                    <a href="/docs/Nextjs/intro-nextjs" class="nav__icons" > <img src="/icons/nextjs.svg" title="Nextjs" alt="Nextjs" /> </a>
                    <a href="/docs" class="nav__icons"> <img src="/icons/Logo-512X512.png" title="Docs" alt="Docs" /> </a>
+                   <a href="/docs/Docker/intro" class="nav__icons"> <img src="/icons/docker.svg" title="Docker" alt="Docker" /> </a>
                  </div>
                </div>`,
             },