fix: prevent users from creating timeslots in the past

closes #125

src/Pages/EmissionManager.vue

@@ -351,6 +351,9 @@ export default {
         select: this.createEvent,
         selectable: true,
         selectMirror: true,
+        selectAllow({ start }) {
+          return start > new Date()
+        },
         navLinkDayClick(selectedDate) {
           selectDay(selectedDate)
           document