Fixing the "exceeds GitHub's file size limit" error

This is easily done, you've zipped up your site to upload to a server and pushed to GitHub, you then get an error message like this:

remote: error: File is 214.15 MB; this exceeds GitHub's file size limit of 100.00 MB


 ! [remote rejected] master -> master (pre-receive hook declined)

error: failed to push some refs to ...

This helpful page from github has a solution. The steps are also below: