DataFrame#vectors= should change the name of the vectors in @data.

[genya0407]

DataFrame#vectors= changes @vectors variable, however, the name of the vectors in @data is not changed.

irb(main):002:0> df = Daru::DataFrame.new(a: [1,2,3])
=> #<Daru::DataFrame(3x1)>
       a
   0   1
   1   2
   2   3
irb(main):004:0> df.vectors = Daru::Index.new [:b]
irb(main):005:0> df
=> #<Daru::DataFrame(3x1)>
       b
   0   1
   1   2
   2   3
irb(main):006:0> df[:b]
=> #<Daru::Vector(3)>
       a
   0   1
   1   2
   2   3

DataFrame#vectors= should change the name of vectors in @data.

[v0dro]

@genya0407 can you please rebase with the current master?