Maven and Gradle samples for dataflow server

- Minimal and fully working sample of building custom
  dataflow server adding mysql driver.

custom-dataflow-builds/dataflow-server-21x/src/test/java/com/example/customdataflowserver/CustomDataflowServerApplicationTests.java

@@ -0,0 +1,19 @@
+package com.example.customdataflowserver;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase.Replace;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@AutoConfigureTestDatabase(replace = Replace.ANY)
+public class CustomDataflowServerApplicationTests {
+
+	@Test
+	public void contextLoads() {
+	}
+
+}