message: Report on specific errors moving rows in schema 3.
  Continue if migrating user_tokens fails with an apology.
diff: @@ -27,10 +27,9 @@ export class Schema implements IDbSchema {
  // Move old data to new tables.
  return this.moveUserIds(store);
  }).then(() => {
  - log.info("SchemaV3", "Dropping user_tokens. Check backup database for table.");
  // Drop old table.
  return store.db.execAsync(
  - `DROP TABLE user_tokens;`,
  + `DROP TABLE IF EXISTS user_tokens;`,
  );
  });
  }
  @@ -88,10 +87,20 @@ export class Schema implements IDbSchema {
  $discordId: discordId,
  $userId: row.userId,
  });
  + }).catch((err) => {
  + log.error(`Couldn't move ${row.userId}'s token into new table.`);
  }));
  }
  return Bluebird.all(promises);
  - });
  + }).catch((err) => {
  + log.error(`
  +Could not select users from 'user_tokens'.It is possible that the table does
  +not exist on your database in which case you can proceed safely. Otherwise
  +a copy of the database before the schema update has been placed in the root
  +directory.`);
  + log.error(err);
  + return Promise.resolve();
  + }));
  }
  }
  