Fix Dockerfile

[KesterTan]

Dockerfile install docker command is outdated and causes issues when running the autograder. This PR fixes the issues by installing docker using the package manager.

[coderabbitai]

📝 Walkthrough

Walkthrough

The Dockerfile has been updated to replace a simple curl-based Docker installer with a secure, multi-step installation sequence. The new approach includes apt-get update, GPG key setup, Docker repository configuration, and explicit installation of Docker packages with proper cleanup.

Changes

Cohort / File(s)	Summary
Docker Installation Enhancement Dockerfile	Replaced single-line curl-based Docker installer with secure multi-step apt-based installation including GPG keyring setup, Docker repository addition with signed-by verification, and explicit installation of docker-ce, docker-ce-cli, containerd.io, and Docker plugins

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title 'Fix Dockerfile' is vague and generic, using non-descriptive terms that don't convey meaningful information about the specific change.	Make the title more specific about the main change, such as 'Replace curl-based Docker installer with apt package manager installation' or 'Update Dockerfile to install Docker via package manager'.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description clearly explains the problem (outdated Docker installation method causing issues) and the solution (installing Docker via package manager), which aligns with the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch docker-fix

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

Dockerfile (1)

41-52: Solid Docker installation approach following official guidelines.

This follows Docker's recommended installation method for Ubuntu, with good practices like set -eux for fail-fast behavior and proper cleanup.

Minor observation: ca-certificates and curl are already installed in lines 20 and 32. You could simplify line 43 to just install gnupg:

-    DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends ca-certificates curl gnupg; \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends gnupg; \

This is optional since apt handles already-installed packages gracefully.

📜 Review details

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 92ae12f and a3670d8.

📒 Files selected for processing (1)

• Dockerfile