should render the container with container-fluid class or the container will have a fixed width.
<div class="navbar">
<div class="container-fluid">
<!-- .navbar-toggle is used as the toggle for collapsed navbar content -->
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<!-- Everything in here gets hidden at 940px or less -->
<div class="navbar-collapse collapse">
<!-- menu items gets rendered here instead -->
</div>
</div>
</div>
<%= nav_bar responsive: true %>
should render the container with container-fluid class or the container will have a fixed width.