As the title says

How can i get a container to wrap around the rows?

example

<div class="container">
<div class="col-md-6">content</div>
<div class="col-md-6">content</div>
</div>

The example on the bootstrap page shows this

<div class="container">
<div class="row">
<div class="col">
1 of 2
</div>
<div class="col">
1 of 2
</div>
</div>
<div class="row">
<div class="col">
1 of 3
</div>
<div class="col">
1 of 3
</div>
<div class="col">
1 of 3
</div>
</div>
</div>

Thanks

First of all: the rows are the outermost entity, you can't wrap them into anything.
The column spans will be regulated by the break points. You don't have to worry about them. Just make your adjustments at each breakpoint, the rest will be taken care of.

Thanks Inger

Yes the official Bootstrap Docs http://v4-alpha.getbootstrap.com/layout/overview/ (see: containers) state that a container or container-fluid needs to be nested around in order to use their grid.
RBB and RSD both do not have this in their program but the grid still works.
If you really want to wrap everything...One option is go to GRID and change (apply to) to TYPE and add the class of container or container-fluid...this will add the class to the BODY of your page and thus wrap the whole page.