What is the difference between the properties "id" and "cid" on a model object in Backbone.js?
In Backbone.js, the "id" property on a model is automatically assigned based on the "id" set in the model's attributes hash. This is the ID that we receive from the rest of API for the resource that we are querying. On the other hand, the "cid" is a temporary ID assigned to each model and is useful until an actual ID is assigned for the object.
For example, a model pushed to a collection that has not yet been persisted can be called "cid", until it is saved in the database and an actual ID is generated for it. After that, it can be called "id".
