README.md in ohloh_scm-2.0.1 vs README.md in ohloh_scm-2.1.0

@@ -47,13 +47,20 @@
 hg 1.1.2  
 
 If you are using CVS instead of CVSNT, you can potentially try creating
 a shell alias or symlink mapping 'cvsnt' to 'cvs'.
 
+Ohloh SCM uses [posix-spawn](https://github.com/rtomayko/posix-spawn) to
+execute commands so ensure *posix-spawn* gem is installed
+
+``gem install posix-spawn``
+
+
 ## Usage with Bundler
 
 ```
 gem 'ohloh_scm', git: 'https://github.com/blackducksw/ohloh_scm/', require: 'scm'
+gem 'posix-spawn'
 ```
 ## Running
 
 Ensure that cvsnt, svn, svnadmin, svnsync, git, and hg are all on your path. You'll also need to ensure that you have the xmloutput plugin installed for bazaar.