Changed method of requesting many records

Before this commit, multiple records are queried
using `/users?ids=1,2,3` syntax, which uses the
Index route in fortune. This route might be absent
if `.noIndex()` has been called.

With this commit the Fortune and JSONAPI-conformant
method of requesting by joining the ids with commas
is used: `/users/1,2,3`.
Merge pull request #10 from thriqon/master

Changed method of requesting many records