Document how sqlalchemy handles transaction aborts or the best practice to handle transaction aborts (for the readwrite transactions)

[yuanyuan-gl]

Could you please help document the best practice to handle transaction aborts and the errors like “The transaction was aborted and could not be retried due to a concurrent modification.” There were multiple support cases asking about this.

Thanks!

[asthamohta]

We are about to merge this: #243
Thanks for reaching out!