fn add_row_mut(&mut self, v: &Self::Vec) {
        assert_eq!(self.col, v.len());
        match self.shape {
            Shape::Row => {
                self.data.extend_from_slice(&v[..]);
                self.row += 1;
            }
            Shape::Col => {
                self.change_shape_mut();
                self.data.extend_from_slice(&v[..]);
                self.row += 1;
            }
        }
    }
Add row (Mutable)

```
#[macro_use]
extern crate peroxide;
use peroxide::fuga::*;

fn main() {
let mut a = ml_matrix("1 2 3;4 5 6");
let b = c!(7,8,9);
a.add_row_mut(&b);
assert_eq!(a, ml_matrix("1 2 3;4 5 6;7 8 9"));
}
```
src/traits/sugar.rs