Bug in redshift_batch when querying db.

[jorgeorpinel]

The bug is here: https://github.com/heroku-examples/analytics-with-kafka-redshift-metabase/blob/master/redshift_batch/index.js#L35

2nd line below:

      const query = Postgres.helpers.insert(queue, ecommTable);
      db.query(query, queue) // <-- `queue` not needed and can cause problems.

queue was already used for Postgres.helpers.insert (ref) so query is already a pure string. However it may contain dollar signs so sending queue (again) to db.query can cause errors.

Just remove ", queue".