Make stamps database capable of using alphanumeric IDs for users

[tayler6000]

No description provided.

[jmccuen]

What's the motivation for this, given that all discord user ids are integers and we use discord auth for the wiki, so all wik users have a discord id? Is this to support users from other systems such as Slack etc?

The easiest thing to do would be to just change the DB schema and make sure whenever we use Discord IDs to cast them as strings; we'd just need to do some testing to make sure nothing breaks if there are IDs in this table that dont exist in e.g. the discord user list

[tayler6000]

This is a low priority, but Stampy is configured to work with slack and flask as well, and their IDs are alphanumeric.