Update README.md - Githubissues

Looks awesome @skirmer! A couple comments to streamline -

I'd just link "CMS.gov" in the Original Source section to the link you have in the doc
Could you add a sentence to quickly summarize what the dataset contains? Along the lines of "This is a table showing drug brand names and other information alongside manufacturers" or whatever other description makes sense?
For the README, we're aiming for a quick snapshot of what each data source can broadly tell us, then we'll include specific details in the data dictionary for when people see the summary and then want to dig into it. I think in this case, info like ASOFDATE and the 2016-17 note would be good examples of data dictionary info (here's the current data dictionary template - very helpful and necessary, and better suited for the dictionary than the overview so they get proper attention at the right time.

I'll add a note to the README to clarify what should go there vs the data dictionary!

Data4Democracy / drug-spending