Error: Could not symlink include/node/common.gypi /usr/local/include/node is not writable.

    sudo chown -R `whoami`:admin /usr/local/include/node
    sudo chown -R `whoami`:admin /usr/local/bin
    sudo chown -R `whoami`:admin /usr/local/share
    sudo chown -R `whoami`:admin /usr/local/lib/dtrace 

    brew link --overwrite node