add no sessions message

ui/session-list.css

@@ -25,6 +25,11 @@
     border-radius: 5px;
     margin: 1em;
 
+    &.-text {
+      display: block;
+      text-align: center;
+    }
+
     >.theirname {
       font-weight: bold;
       grid-area: their-name;

ui/session_list.js

@@ -7,6 +7,9 @@ export default class SessionList {
   view({attrs: { models, onSelect, onDelete } }) {
     return m("section.wb-session-list", [
       m("ol", [
+        models.length === 0
+          ? m("li.item.-text._alternate._apply", "Du hast no koane Sätz…")
+          : null,
         models.map((s, i) => m("li.item._alternate._apply", [
           m("span.theirname", s.theirTeam !== "" ? s.theirTeam : "Se"),
           m("span.ourname", s.ourTeam !== "" ? s.ourTeam : "Mia"),