/usr/lib/libruby-1.9.1.so is in ruby1.9.1-dev 1.9.3.194-8.1+deb7u5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libruby-1.9.1.so.1.9.1
/usr/lib/libruby-1.9.1.so.1.9.1