fixed nav hamburger not showing

Author: vincentlieu

app/views/shared/_navigation_bar.html.erb

@@ -1,5 +1,8 @@
 <nav class="navbar navbar-expand-lg navbar-dark bg-dark">
   <%= link_to "HYPERBOLIC", root_path, class: "navbar-brand" %>
+    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
+      <span class="navbar-toggler-icon"></span>
+    </button>
   <div class="collapse navbar-collapse" id="navbarSupportedContent">
     <ul class="navbar-nav ml-auto">
         <%= link_to "Browse", listings_path, class: "nav-link" %>