Bootstrap - Fix Div to bottom of div - css

Question

I have a div, and in that div, I have another div. I am trying to pin the inner div to the bottom of the outer div using specifically bootstrap classes, but I cant seem to find a bootstrap method to do this. I've also tried using just regular CSS, but cant get this working. I tried veritical-align: bottom; and setting the position to absolute.
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" />
<div class="card-body">
<ul class="list-unstyled mt-3 mb-4" style="text-align: left;">
<li>stuff</li>
</ul>
<div>
<button type="button" class="btn btn-outline-primary">Edit</button>
<button type="button" class="btn btn-outline-primary">Delete</button>
</div>
</div>

Answer 1

To get it done using Bootstrap 4 classes, you just add the classes d-flex flex-column to the card-body and then add the mt-auto class (margin-top:auto) to the inner div like so:
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<div class="card-body d-flex flex-column">
<ul class="list-unstyled mt-3 mb-4" style="text-align: left;">
<li>stuff</li>
</ul>
<div class="mt-auto">
<button type="button" class="btn btn-outline-primary">Edit</button>
<button type="button" class="btn btn-outline-primary">Delete</button>
</div>
</div>
That will always keep the inner div pinned to the bottom.

Answer 2

Is this what you are trying to achieve??
.card-body {
border: 4px solid blue;
position: relative;
}
.inner {
border: 4px solid red;
position: absolute;
bottom: -50px;
}
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" />
<div class="card-body">
<ul class="list-unstyled mt-3 mb-4" style="text-align: left;">
<li>stuff</li>
</ul>
<div class="inner">
<button type="button" class="btn btn-outline-primary">Edit</button>
<button type="button" class="btn btn-outline-primary">Delete</button>
</div>
</div>