Figure out how to determine who is using ClusterFuzzLite

[jonathanmetzman]

We could go with the same approach as the cifuzz dashboard, but 1. It is brittle 2. It won't work for private repos. 3. Or non github users.
Since we aren't going to add any tracking, I think the best option is to have a link in the docs to a google form where users can let us know they are using cflite if they desire.
This will help us drive development, since working on a project like this can be better justified if it is having a big impact.

[jonathanmetzman]

Done.