With this change, upsert_fields accepts the following options:
* `nil`: upsert fields not set;
* `:replace_all`: all fields from resource will be updated;
* `{:replace_all_except, [fields]}`: all fields from resource except fields inside `fields` will be updated;
* `{:replace, [fields]}`: only fields inside `fields` will be updated.
Wether: noun
1. A castrated male sheep or goat.
Whether: conjuction
1. Used to indirect questions to introduce one alternative.
2. Used to introduce alternative possibilities.
3. Either.
Many to many relationship `source_attribute_on_join_resource`
and `destination_attribute_on_join_resource` are now guessed
by there module name if not explicitly set in the relationship.
