Update instructions for testing with your own CCM branch

patch by Ekaterina Dimitrova, reviewed by Berenguer Blasi and Josh McKenzie for CASSANDRA-17182

README.md

@@ -90,6 +90,8 @@ test fails, the logs for the node are saved in a `logs/<timestamp>` directory
 for analysis (it's not perfect but has been good enough so far, I'm open to
 better suggestions).
 
+In case you want to run tests using your own CCM branch, please, refer to the comments in requirements.txt for details how to do that.
+
 Writing Tests
 -------------
 

requirements.txt

@@ -6,6 +6,9 @@
 # git tag -a -f cassandra-test
 # git push origin :refs/tags/cassandra-test
 # git push -f origin refs/tags/cassandra-test
+#
+# In case you want to test a patch with your own CCM branch, further to changing below CCM repo and branch name, you need to add -e flag at the beginning
+# Example: -e git+https://github.com/userb/ccm.git@cassandra-17182#egg=ccm
 git+https://github.com/riptano/ccm.git@cassandra-test#egg=ccm
 decorator
 docopt