array_groups 0.0.1
[1,2,3,4,5].in_groups(2) => [[1,2,3],[4,5]], [1,2,3,4,5].in_groups_of(2) => [[1,2][3,4],[5]], [1,2,3,4,5].in_groups_of(2, nil_fill: true) => [[1,2][3,4],[5,nil]]
[1,2,3,4,5].in_groups(2) => [[1,2,3],[4,5]], [1,2,3,4,5].in_groups_of(2) => [[1,2][3,4],[5]], [1,2,3,4,5].in_groups_of(2, nil_fill: true) => [[1,2][3,4],[5,nil]]