ERROR: While executing gem … (Errno::EPERM) Operation not permitted – /usr/bin/fluent-cat

ERROR:  While executing gem … (Errno::EPERM)

    Operation not permitted – /usr/bin/fluent-cat

As it has been pointed out below, this is a cleaner way of doing it, instead of getting around the Security features of OS X.

sudo gem install -n /usr/local/bin cocoapods