Broken link to ceres_catkin: catkin_simple

Hi!
I am trying to use ceres, but when building it, I get the following error:

CMake Error at gflags_catkin/CMakeLists.txt:4 (find_package):
By not providing "Findcatkin_simple.cmake" in CMAKE_MODULE_PATH this
project has asked CMake to find a package configuration file provided by
"catkin_simple", but CMake did not find one.
I actually tried to build ceres without pulling the following git repository because the link is broken.
https://github.com/ethz-asl/catkin_simple
Could you please make it available again?

Thanks in advance,