Description on tag pages

[simonw]

This pull request introduces the ability to add descriptions to tags within the blog application, enhancing the tag functionality by allowing for more detailed information about each tag to be stored and displayed.

• Adds a description TextField to the Tag model in blog/models.py, allowing descriptions to be stored for each tag.
• Updates the TagAdmin class in blog/admin.py to include the description field, enabling it to be edited through the Django admin interface.
• Modifies the view handling /tags/x/ in blog/views.py to include the tag's description in the context passed to the template, making the description available for display.
• Updates the template templates/archive_tag.html to display the tag's description at the top of the page if it exists, providing users with more context about the tag.
• Adds a migration file blog/migrations/0020_tag_description.py to apply the changes to the database schema, ensuring the new description field is properly integrated.

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For more details, open the Copilot Workspace session.

[simonw]

This was an experimental live demo of Copilot Workspace. I prompted:

Add a feature that lets me add a description to my tag pages, stored in the database table for tags and visible on the /tags/x/ page at the top

I thought this would be an interesting demo because it would need to demonstrate understanding of a variety of different files within the project.

With hindsight it wasn't a great demo - the solution is pretty simple and I could have implemented it myself much faster than using Workspace. It did figure out a working solution (after I reminded it to create a migration) which worked as intended when I tested it locally - I then did a bunch of my own changes to make it better fit my taste.

[simonw]

https://simonwillison.net/tags/datasette/ illustrates the shipped feature:

Here's a dashboard showing other tags I've added a description to: https://simonwillison.net/dashboard/tags-with-descriptions/