fix: remove unapproved sv-SE Gutenberg sentences (#656)

server/migrations/20221208220000-remove-not-yet-approved-sv-sentences-gutenberg.js

@@ -0,0 +1,24 @@
+'use strict';
+
+// https://discourse.mozilla.org/t/high-amount-of-low-quality-submissions-in-sentence-collector-makes-reviewing-boring/108368
+
+module.exports = {
+  up: (queryInterface) => {
+    return  queryInterface.sequelize.query(`
+      WITH IDsToDelete AS (SELECT
+          Sentences.id
+        FROM Sentences
+        LEFT JOIN Votes ON (Votes.sentenceId=Sentences.id)
+        WHERE
+          Sentences.localeId = "sv-SE" AND
+          Sentences.source = "Project Gutenberg, with slight tweaks by me."
+        GROUP BY Sentences.id
+        HAVING
+          COUNT(Votes.approval) < 2 OR
+          COUNT(Votes.approval) = 2 AND SUM(Votes.approval) = 1
+      )
+      DELETE FROM Sentences WHERE id IN (SELECT id FROM IDsToDelete);
+    `);
+  },
+  down: () => Promise.resolve(),
+};