adjacency_matrix::add_vertex always aborts in Debug mode ?

I found this in `graph/adjacency_matrix` ligne 966 :

```cpp
template < typename D, typename VP, typename EP, typename GP, typename A >
inline typename adjacency_matrix< D, VP, EP, GP, A >::vertex_descriptor
add_vertex(adjacency_matrix< D, VP, EP, GP, A >& g)
{
// UNDER CONSTRUCTION
BOOST_ASSERT(false);
return *vertices(g).first;
}
```
Does it mean there is no way to add vertices to an already-constructed adjacency_matrix ? Am i missing something ?