[doc][skip ci] Add sponsoring section.

Author: makasim

README.md

@@ -1,3 +1,12 @@
+<h2 align="center">Supporting Enqueue</h2>
+
+Enqueue is an MIT-licensed open source project with its ongoing development made possible entirely by the support of community and our customers. If you'd like to join them, please consider:
+
+- [Become a sponsor](https://www.patreon.com/makasim).
+- [Become our client](http://forma-pro.com/)
+
+---
+
 # Symfony Async Command.
 
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