Driver: Add page about Crystal

[amotl]

About

What the title says.

Preview

https://cratedb-guide--421.org.readthedocs.build/connect/crystal/

[coderabbitai]

Walkthrough

This pull request adds Crystal driver documentation to CrateDB, introducing a new grid card in the drivers index and a comprehensive Crystal-specific connection guide with installation instructions, code examples, and SSL configuration details.

Changes

Cohort / File(s)	Summary
Drivers index expansion docs/connect/index.md	Adds Crystal as a new grid-item-card under the "Drivers by language" section with corresponding logo, link, and alt text; extends toctree to include crystal/index
Crystal driver documentation docs/connect/crystal/index.md	New documentation page covering Crystal database connectivity: includes prerequisites, shard.yml configuration, example code using crystal-pg via crystal-db, installation and execution commands, SSL connection setup with auth methods, and references to Crystal database driver resources

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Possibly related PRs

• Driver: Add page about Julia #417: Follows the same pattern of adding a language driver card and corresponding language-specific documentation page
• Driver: Add page about Kotlin #423: Implements identical changes—adding a driver card and new language-specific docs page
• Driver: Add page about Scala #412: Uses the same approach to expand drivers documentation with a new language card and separate documentation file

Suggested labels

cross linking

Suggested reviewers

• surister
• seut

Poem

🐰✨ A crystal shines in the docs so bright,
New guides for drivers, a beautiful sight!
From index.md to pages brand new,
Connection examples, Crystal comes through! 💎

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'Driver: Add page about Crystal' clearly and specifically describes the main change: adding documentation for connecting to CrateDB from Crystal applications.
Description check	✅ Passed	The description relates to the changeset by confirming the addition of a Crystal driver page, though it is minimal and relies on the title to convey the main change.
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 crystal

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[amotl]

Problem

When not permitting auth_methods=cleartext, the connection will fail, because cleartext is disabled by default.

Unhandled exception:  (DB::ConnectionRefused)
Caused by: server asked for disabled authentication method: cleartext (PQ::ConnectionError)

Background

By default this driver will accept scram-sha-256 and md5, as well as
trust. However cleartext is disabled by default. You can control exactly
which auth methods the client will accept by passing in a comma separated list
to the auth_methods parameter.

-- https://github.com/will/crystal-pg/blob/c5b8ac1ac5713fc58f974d8a4327887a0b297594/README.md?plain=1#L164-L169

Thoughts

Do you think it is applicable to report this to crate/crate, so it may possibly support md5 or scram-sha-256 in the future?

/cc @matriv, @seut

[amotl]

I've created a ticket about this, so we can proceed.

• Support SCRAM-SHA-256 password encryption crate#18943

[kneth]

Let's discuss https://github.com/crate/tech-content/issues/124#issuecomment-3485676563 before merging