Allow board delete via UI

ref #16

client/src/util/api.js

@@ -13,6 +13,12 @@ export class APIClient {
     ;
   }
 
+  deleteBoard(id) {
+    return fetch(`/api/boards/${id}`, {
+      method: 'DELETE'
+    });
+  }
+
   fetchBoards() {
     return fetch(`/api/boards`)
       .then(res => res.json())