GET: /muh/2/?filter[first_name]=foo&filter[last_name]=muh
results in
filter["first_name"] = foo
filter["last_name"] = muh
GET: /muh/2/?filter[first_name]=foo&filter[first_name]=muh
results in
filter["first_name"].get(0) = foo
filter["first_name"].get(1) = muh