Added instructions for brew based setup release

README

@@ -31,7 +31,11 @@ python setup.py sdist --format=zip,gztar
 
 On Mac OS X:
 
+  # On port based installs
   sudo python setup-release.py py2app
+  # On brew installs
+  ARCHFLAGS="-arch i386 -arch x86_64" sudo /usr/bin/python setup-release.py py2app --includes sip
+
   sudo hdiutil create -fs HFS+ -volname "Electrum" -srcfolder dist/Electrum.app dist/electrum-v0.61-macosx.dmg