Destroyed connection before restoring DB file

no issue

- we've seen some instances of SQLite saying "database disk image is malformed"
- I think this happens because we copy the file whilst we are still connected to
  the old DB
- this commit destroys the connection before copying the clean file to the live
  DB file

test/utils/db-utils.js

@@ -26,6 +26,7 @@ module.exports.reset = async () => {
         const dbExists = await fs.pathExists(filenameOrig);
 
         if (dbExists) {
+            await db.knex.destroy();
             await fs.copyFile(filenameOrig, filename);
         } else {
             await knexMigrator.reset({force: true});