This is quick and dirty post, because I run into this problem all the time and need a place to find the answer quickly.
Here is what happens:
ImportError: libcudart.so.8.0: cannot open shared object file: No such file or directory
Here is the answer:
drcrook@BigBen:/usr/local/cuda$ sudo cp include/cudnn.h /usr/include drcrook@BigBen:/usr/local/cuda$ sudo cp lib64/libcudnn* /usr/lib/x86_64-linux-gnu/ drcrook@BigBen:/usr/local/cuda$ sudo chmod a+r /usr/lib/x86_64-linux-gnu/libcudnn*
If you are struggling getting your GPU initialized with Theano, Tensorflow or really any deep learning framework, this is probably something you may want to do.