add react-express-mysql application sample

Signed-off-by: Anca Iordache <anca.iordache@docker.com>

samples/react-express-mysql/frontend/src/test/mocks/imageMock.js

@@ -0,0 +1,3 @@
+// Return an empty string or other mock path to emulate the url that
+// Webpack provides via the file-loader
+module.exports = 'mocked-image.jpg';

samples/react-express-mysql/frontend/src/test/mocks/styleMock.js

@@ -0,0 +1,2 @@
+// Return a Proxy to emulate css modules (if you are using them)
+module.exports = require('identity-obj-proxy');