Add missing indexes on foreign keys and frequently queried columns

[gnclmorais]

Description of the issue 📄

Our website is good but it could be better, namely regarding speed in a few places. Running Claude Code on the repo, it suggested adding a few missing database indexes that, according to it, would “10-100x faster queries on foreign key lookups”.

Steps to fix 🛠

Add the following indexes in a migration:

    add_index :invitations, :event_id unless index_exists?(:invitations, :event_id)
    add_index :invitations, :member_id unless index_exists?(:invitations, :member_id)
    add_index :workshop_invitations, :workshop_id unless index_exists?(:workshop_invitations, :workshop_id)
    add_index :workshop_invitations, :member_id unless index_exists?(:workshop_invitations, :member_id)
    add_index :events, :date_and_time unless index_exists?(:events, :date_and_time)
    add_index :attendances, [:attendable_type, :attendable_id] unless index_exists?(:attendances, [:attendable_type, :attendable_id])

To do 📋

• Claim this issue (comment below, or assign yourself if you are part of the codebar org)
• Fork and clone the repository
• Update the relevant files. Follow the steps to fix section in this issue.
• Commit your changes as one commit. Use the title of this issue as your commit message
• Submit a pull request
• Mention this issue in the PR description by including it's number
• Have your pull request reviewed & merged by a codebar team member

[mroderick]

Thank you for looking into low hanging fruit to make the website faster!

It would be helpful if you could show which queries / features would be improved per added index, so whoever takes this on would have a good chance at determining if adding an index made a positive difference.

[gnclmorais]

I actually just merged a PR addressing this (or at least some of the ones I found), so I’m closing this :)