Add roadmap to readme

Author: theoriginalbit

README.md

@@ -1,5 +1,12 @@
 # Passive Alert View ![Build](https://github.com/a2i2/passive-alert-view/workflows/Build/badge.svg?branch=master)
 
+## Roadmap
+
+- [ ] Documentation
+- [ ] Add accessibility support
+- [ ] Implement support for `PassiveAlertView.Theme.Background.blur`
+- [ ] Implement support for `PassiveAlertView.Theme.Background.gradient`
+
 ## Contributing
 
 Contributions are most welcome. Before submitting an issue or pull request, please familiarise yourself with the [Contribution Guidelines](./CONTRIBUTING.md).