Persisted Plus Tier migration

This is basically 100% perf optimization

migrations/017-persisted-plus-tier.js

@@ -0,0 +1,67 @@
+module.exports.up = function (db) {
+  db.prepare(`drop view "PlusTier"`).run();
+
+  db.prepare(
+    /* sql */ `
+    create view "FreshPlusTier" as
+    select
+      "votedId" as "userId",
+      min(
+        case
+          when "passedVoting" = 0
+            and "wasSuggested" = 1 then null
+          when "passedVoting" = 1 then "tier"
+          when "passedVoting" = 0
+            and "tier" != 3 then "tier" + 1
+        end
+      ) as "tier"
+    from
+      "PlusVotingResult"
+    where
+      year = (
+        select
+          "year"
+        from
+          "PlusVote"
+        where
+          "validAfter" < strftime('%s', 'now')
+        order by
+          "year" desc,
+          "month" desc
+        limit
+          1
+      )
+      and "month" = (
+        select
+          "month"
+        from
+          "PlusVote"
+        where
+          "validAfter" < strftime('%s', 'now')
+        order by
+          "year" desc,
+          "month" desc
+        limit
+          1
+      )
+      group by
+        "votedId";
+  `
+  ).run();
+
+  db.prepare(
+    /* sql */ `
+    create table "PlusTier" (
+      "userId" integer primary key,
+      "tier" integer not null,
+      foreign key ("userId") references "User"("id") on delete set null
+    ) strict
+  `
+  ).run();
+
+  db.prepare(
+    /* sql */ `
+    insert into "PlusTier" ("userId", "tier") select "userId", "tier" from "FreshPlusTier" where "tier" is not null;
+  `
+  ).run();
+};