Updated Notify_onesignal (markdown)

Notify_onesignal.md

@@ -62,3 +62,40 @@ apprise -vv -t "Test Message Title" -b "Test Message Body" \
 apprise -vv -t "Test Message Title" -b "Test Message Body" \
    onesignal://abc123@a6k4ABnck26hDh8AA3EDHoOVdDEUlw3nty/3456-2345-a3ef?subtitle=A%20Different%20Subtitle
 ```
+
+### Custom Data (Templates)
+Making use of the `:` on the Apprise URL allows you to alter and add to the payload of your onesignal post.
+
+```bash
+# As an example:
+apprise -vv -b "Test Message Body" \
+   "onesignal://credentials/?:key1=value1"
+```
+
+The above would additional these assignments into the payload  as `custom_data':
+```json
+{
+   ... previous payload elements... and then:
+   "custom_data": {"key1": "value1"}
+}
+```
+
+
+### Data
+Making use of the `+` on the Apprise URL allows you to alter and add to the payload of your onesignal post.
+
+
+```bash
+# As an example:
+apprise -vv -b "Test Message Body" \
+   "onesignal://credentials/?+key1=value1"
+```
+
+The above would additional these assignments into the payload  as `data':
+```json
+{
+   ... previous payload elements... and then:
+   "data": {"key1": "value1"}
+}
+```
+