Start saving in Offer Entity - rawOffer ID and provider

[RobertCzaja]

You don't have to save provider name for now because all offers came from JJIT, on getting another provider that column should be implemented

[RobertCzaja]

• [x] gets MongoDB Document ID from code
• [x] add new properties to Offer entity
• [x] provide values for Production Code Offer Entity and for the testing one
• [x] add new columns (in new table offer_provider)
• [ ] create CLI to migrate all historical Offer

[RobertCzaja]

🟥 The last step "create CLI..." - won't do - because there is no reason to do that except having a consistent data - but system can operate with that