Updated post endpoint to return 400 on DB integrity error
Updated post endpoint to return 400 on DB integrity error

mtekel/digitalmarketplace-api,mtekel/digitalmarketplace-api,mtekel/digitalmarketplace-api,RichardKnop/digitalmarketplace-api,RichardKnop/digitalmarketplace-api,mtekel/digitalmarketplace-api,RichardKnop/digitalmarketplace-api,RichardKnop/digitalmarketplace-api,alphagov/digitalmarketplace-api,alphagov/digitalmarketplace-api,alphagov/digitalmarketplace-api