Currently posting and saving status to DB aren't atomic.
After a successful call to GH if DB update failed review will be duplicated.

Proposed solution:
If we create review without body attribute, it will be visible to an user only after the submit call.

It's safe to call submit multiple times.

Steps:

• Call create without body if it doesn't have ID of review in DB already
• Save returned ID to DB
• In case of failure, we can just retry later without any issues for an end user
• Send confirm (submit)
• Update status in DB
• In case of failure, we can just safely retry later