Add TODOs Badge to README

Moved from GitHub dgraph/5347

Posted by patrickdevivo:

Hi there! I wanted to propose adding the following badge to the README to indicate how many TODO comments are in this codebase:


The badge links to which is a free service that indexes and displays TODO comments in public github repos. It can help surface latent work and be a way for contributors to find areas of code to improve, that might not be otherwise documented.

The markdown is:


Thanks for considering, feel free to close this issue if it’s not appropriate or you prefer not to!

(full disclosure, I am the creator/maintainer of tickgit)