Add information which version of slickgrid is used and on how to upgrade it
The readme states that https://github.com/mleibman/SlickGrid is used but not its version.
This information is important namely because this repo is not updated since 2016.
It might be a good idea to migrate to https://github.com/6pac/SlickGrid as stated in the original repo.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information