Passing a sequence by reference to a data type

[ameerwasi]

Ok, it's only been a few days of me learning nim, so this may as well be one of 
the basic things but, Idk. So my problem is that when I make a sequence and 
pass it's shallow copy to a data type and add to it, only the sequence inside 
the data type gets added to. To better illustrate this, here's a piece of code 
    
    
    type
      lis = ref object of RootObj
        v : seq[int]
    
    
    let s = @[1, 2, 3, 4, 5]
    let list = lis()
    shallowCopy(list.v, s)
    
    list.v.add(6)
    echo list.v
    echo s
    
    
    Run

and it outputs 
    
    
    @[1, 2, 3, 4, 5, 6]
    @[1, 2, 3, 4, 5]
    
    
    Run

but I expected it to output this 
    
    
    @[1, 2, 3, 4, 5, 6]
    @[1, 2, 3, 4, 5, 6]
    
    
    Run

Now, if this can't be done with sequences, can you please point me to a data 
structure that allows push, pop, and insertion where this can be done. Thanks 
in advance.