Meta topic: https://meta.discourse.org/t/stumped-about-launcher-rebuild-app-error-process-pid-2096/333876?u=osama.
Follow up to 19672faba6.
The migration that adds the invite link to the sidebar determines the position of the link by looking up the max position that a primary link has and inserts the invite link at the max position plus 1. This approach works fine for most sites, however, sites that have deleted all primary links from the sidebar will fail because the max position will be `nil` which blows up the migration.
This commit addresses this edge case by falling back to looking up the min position of secondary links, or to zero if there're also no secondary links, and then inserts the invite link at the min position minus 1.
This commit adds a new "Invite" link to the sidebar for all users who can invite to the site. Clicking the link opens the invite modal without changing the current route the user is on. Admins can customize the new link or remove it entirely if they wish by editing the sidebar section.
Internal topic: t/129752.
Osama Sayegh