BUG: Use datepicker in collection form (#81)

Fixes #73

app/transforms/ccdb-date.js

@@ -0,0 +1,18 @@
+import DS from 'ember-data';
+
+export default DS.Transform.extend({
+  deserialize(serialized) {
+    return serialized || '';
+  },
+
+  serialize(date) {
+    if (date !== '') {
+      const day = date.getDate();
+      const month = date.getMonth() + 1;
+      const year = date.getFullYear();
+      return `${year}-${month}-${day}`;
+    } else {
+      return null;
+    }
+  }
+});