contributing guide: link fix

Author: Peter

CONTRIBUTING.md

@@ -1,6 +1,6 @@
 Submit a new issue only if you are sure it is a missing feature or a bug. Otherwise discuss the topic on the 
-[mailing list](http://graphhopper.com/#developers) first. For new translations or problems in an existing one
-please refer to [this documentation](https://github.com/graphhopper/graphhopper/edit/master/docs/index.md).
+[mailing list](http://graphhopper.com/#developers) first. For new translations or fixes to existing translations
+please refer to [this documentation](https://github.com/graphhopper/graphhopper/blob/master/docs/core/translations.md).
 
 Issues for newcomers are tagged with 
 ['good first issue'](https://github.com/graphhopper/graphhopper/labels/good%20first%20issue) 
@@ -11,9 +11,9 @@ and documentation issues are taged with
 
 1. [Fork the repo](https://help.github.com/articles/fork-a-repo) and create a branch for your new feature or bug fix.
 
-2. Run the tests. We only take pull requests with passing tests: `mvn test`
+2. Run the tests. We only take pull requests with passing tests: `mvn clean test verify`
 
-3. Add a test for your change or if it is a bug fix create a failing test. Only refactoring and documentation changes
+3. Add at least one test for your change. Only refactoring and documentation changes
 require no new tests. Also make sure you submit a change specific to exactly one issue. If you have ideas for multiple 
 changes please create separate pull requests.