Update README.md

lor6 · web-flow · commit f3bdf6fffbfa · 2019-04-21T10:55:26.000+03:00
diff --git a/testing-modules/groovy-spock/README.md b/testing-modules/groovy-spock/README.md
@@ -2,3 +2,4 @@
 
 - [Introduction to Testing with Spock and Groovy](http://www.baeldung.com/groovy-spock)
 - [Difference Between Stub, Mock, and Spy in the Spock Framework](https://www.baeldung.com/spock-stub-mock-spy)
+- [Guide to Spock Extensions](https://www.baeldung.com/spock-extensions)

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`@@ -2,3 +2,4 @@`
`2`	`2`
`3`	`3`	`- [Introduction to Testing with Spock and Groovy](http://www.baeldung.com/groovy-spock)`
`4`	`4`	`- [Difference Between Stub, Mock, and Spy in the Spock Framework](https://www.baeldung.com/spock-stub-mock-spy)`
	`5`	`+- [Guide to Spock Extensions](https://www.baeldung.com/spock-extensions)`