feat: index tweaks and exclude blank description from search

[JasonChong96]

Problem

Links with no description should be excluded from search as some links should not be discoverable.

Solution

Add a condition to search to exclude urls with blank descriptions

Improvements:

• Index will be managed by sequelize instead
• Explicit configuration of search weights allow easy reconfiguration either through config.ts or env vars
• Empty state graphic should no longer overlap the sort panel
• Nav buttons hidden on search page

Deploy notes:

• Run migration script before deploying on production. This will allow sequelize to create the new updated search index in place of the old one.

[liangyuanruo]

Code lgtm, but one nagging doubt I have is the effect of deploying this to the database during a period of high search usage. It's generally considered bad practice to create indexes on deployment, but the performance impact is probably acceptable give that it takes only ~1s.

Maybe @LoneRifle can advise as well.

[LoneRifle]

You really really should be letting sequelize handle this for you:
https://sequelize.org/master/manual/indexes.html

[JasonChong96]

You really really should be letting sequelize handle this for you:
https://sequelize.org/master/manual/indexes.html

Will check if this is possible for the search index

[LoneRifle]

What's the intention actually? Do you wish to keep the index schema fresher than what sequelize.sync tries to do? Bear in mind that because sequelize.sync uses CREATE X IF NOT EXISTS, it tends to refrain from altering existing db objects

[JasonChong96]

It was initially done with a sql migration script as sequelize doesn't have support for postgres full text search so I didn't think it would be possible to use sequelize's sync for a text search index but that might not be the case

[JasonChong96]

Changed to use sequelize to manage index. Migration script has to be run to drop the previously manually managed index on production before deployment