Add a all repositories button to dropdown (#338)

Author: govindgoel

index.html

@@ -70,6 +70,7 @@ <h1>Welcome to <span class=" org-display-name">Public Lab</span>'s coding commun
             Select repository
           </button>
           <div id="dropdown-container" class="dropdown-menu" aria-labelledby="dropdownMenuButton">
+	    <p class="dropdown-items">all</p>	
           </div>
         </div>
         <!-- DROPDOWN ENDS -->