Update README.md

90499799 · Jan-Philipp Willem · e5b74698 · 90499799
Commit 90499799 authored Oct 15, 2015 by Jan-Philipp Willem
--- a/README.md
+++ b/README.md
@@ -4,6 +4,10 @@
 * Copy `.ruby-version.example` to `.ruby-version`.
 * Reload directory to create rvm gemset.

+## nokogiri
+if there are errors with nokogiri compilation with new xcode7:
+`gem install nokogiri -- --with-xml2-include=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/libxml2 --use-system-libraries`
+
 ## openbabel
 * `brew install cmake` for OSX
 * install openbabel as described in its [documentation](https://github.com/cubuslab/openbabel/blob/master/INSTALL)