Implement authentication and access control

client/css/app.css

@@ -229,11 +229,17 @@ i {
       }
     }
   }
+
   & > .logo {
     margin: 10px;
     display: inline;
     height: 56px;
   }
+
+  & > .user-menu {
+    float: right;
+    margin: 5px;
+  }
 }
 
 #content {
@@ -308,6 +314,10 @@ h3 {
   margin-bottom: 0.5em;
 }
 
+p.error {
+  color: #a00;
+}
+
 /* Remove button padding in FF */
 input::-moz-focus-inner {
   border: 0;