Merge pull request #51 from yast/add_doc_link

add links to reasonable s390 resources

README.md

@@ -3,3 +3,10 @@
 [![Travis Build](https://travis-ci.org/yast/yast-s390.svg?branch=master)](https://travis-ci.org/yast/yast-s390)
 [![Code Coverage Status](
 https://coveralls.io/repos/github/yast/yast-s390/badge.svg?branch=master)](https://coveralls.io/github/yast/yast-s390?branch=master)
+
+## Resources
+
+For s390 development these resources are used:
+
+- https://www.ibm.com/developerworks/linux/linux390/documentation_dev.html
+- https://www.ibm.com/developerworks/linux/linux390/documentation_suse.html (for released products)