add item to the collection with foreign key via REST call

I resolved this issue by using link to the container inside json.

POST { "value" : 666, "date" : "2016-01-31T23:00:00.000+0000","container":"http://localhost:8080/container/1"}

I am not sure if it works without spring-data-rest

EDIT: I should point out, that linked resource has to be @RepositoryRestResource and should be aggregate root.