invites now has a max_uses column and less strict column requirements

server/migrations/2020-02-04-083657_invites/up.sql

@@ -1,7 +1,15 @@
--- Your SQL goes here
+-- @id : id of the invite
+
+-- @expires : unix timestamp of when that invite expries
+-- can be set to null which means it never expires
+
+-- @uses : can be null which means it doesn't have a use limit
+
+-- @max_uses : if this is null uses only ever incremented but we don't care for destroying on that parameter
 CREATE TABLE IF NOT EXISTS `invites` (
 	`id` bigint UNSIGNED NOT NULL,
-	`expires` bigint UNSIGNED NOT NULL,
-	`uses` integer NOT NULL, 
+	`expires` bigint,
+	`uses` integer, 
+	`max_uses` integer,
 	PRIMARY KEY( `id` )
 );