Add Docker microagent for installation and usage (#7027)

Co-authored-by: openhands <openhands@all-hands.dev>

microagents/knowledge/docker.md

@@ -0,0 +1,56 @@
+---
+name: docker
+type: knowledge
+version: 1.0.0
+agent: CodeActAgent
+triggers:
+- docker
+- container
+---
+
+# Docker Installation and Usage Guide
+
+## Installation on Debian/Ubuntu Systems
+
+To install Docker on a Debian/Ubuntu system, follow these steps:
+
+```bash
+# Update package index
+sudo apt-get update
+
+# Install prerequisites
+sudo apt-get install -y apt-transport-https ca-certificates curl gnupg lsb-release
+
+# Add Docker's official GPG key
+curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
+
+# Set up the stable repository
+echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
+
+# Update package index again
+sudo apt-get update
+
+# Install Docker Engine
+sudo apt-get install -y docker-ce docker-ce-cli containerd.io
+```
+
+## Starting Docker in Container Environments
+
+If you're in a container environment without systemd (like this workspace), start Docker with:
+
+```bash
+# Start Docker daemon in the background
+sudo dockerd > /tmp/docker.log 2>&1 &
+
+# Wait for Docker to initialize
+sleep 5
+```
+
+## Verifying Docker Installation
+
+To verify Docker is working correctly, run the hello-world container:
+
+```bash
+sudo docker run hello-world
+```
+