Add Instagram link to page

Author: Travis Southard

html-templates/designs/site-bootstrap4.tpl

@@ -139,6 +139,7 @@
             <div class="row align-items-center">
                 <div class="col-lg-4 text-lg-left"></div>
                 <div class="col-lg-4 my-3 my-lg-0">
+                    <a class="btn btn-dark btn-social mx-2" href="http://instagram.com/codeforphilly"><i class="fab fa-instagram"></i></a>
                     <a class="btn btn-dark btn-social mx-2" href="http://twitter.com/codeforphilly"><i class="fab fa-twitter"></i></a>
 					<a class="btn btn-dark btn-social mx-2" href="https://www.linkedin.com/company/code-for-philly/about/"><i class="fab fa-linkedin-in"></i></a>
 					<a class="btn btn-dark btn-social mx-2" href="https://www.facebook.com/codeforphilly/"><i class="fab fa-facebook-f"></i></a>