Update the application state interface.
Now that we have the standard initial implementation for NgRX and Auto-Entity in place, we need to wire our models into our state.
Note that we have added a new customer property to the IAppState interface of type IEntityState<Customer>, which we imported from @briebug/ngrx-auto-entity at the top of the file.
For most basic CRUD states, you will not need to implement any custom state interfaces, effects or reducers. This is the simplicity that NgRX Auto-Entity brings to the table!
After we create the entity reducer, we'll also need to update the appReducer constant to include the customer property (with the customer reducer function as the value). It's important that both properties have the same name.