react-rust-postgres: create simple client

Signed-off-by: Jérémie Drouet <jeremie.drouet@gmail.com>

react-rust-postgres/frontend/src/setupTests.js

@@ -0,0 +1,5 @@
+// jest-dom adds custom jest matchers for asserting on DOM nodes.
+// allows you to do things like:
+// expect(element).toHaveTextContent(/react/i)
+// learn more: https://github.com/testing-library/jest-dom
+import '@testing-library/jest-dom/extend-expect';