Refactoring: Rename Test for registering a user

projjpn/src/test/java/de/hs_fulda/ciip/projjpn/CustomersTest.java

@@ -16,7 +16,7 @@ public class CustomersTest extends TestCase {
 		assertTrue(nicknameIsAvailable);
 	}
 	
-	public void test_registerUser() {
+	public void test_registerSingleUser() {
 		// Given
 		Customers customers = new Customers();
 		String expectedNickNameInput = "Mougli";