Add contributing.md

[itepifanio]

Hi, great repo idea! I recently gave a talk about data apps with python and this repository would be an excellent example to showcase in that context.

Do you mind adding a contributing.md? I'm not sure how you're installing the dependencies and how the tests are running.

[gshotwell]

What were you thinking should be in that document? The repo doesn't have any tests or build process so it might be better to just include that information in the README

[itepifanio]

What were you thinking should be in that document?

Some guidelines about how to install the deps, how to add a new app into a problem. For example, at sampling-dashboard we have a requirements.txt for all the packages and no individual README.md but at file-monitoring it has its own requirements.txt and README.md, it's not clear how newcomer's code should be structured.

Data it's repeating itself too (nyc-taxi.csv for example), it's a good practice? This kind of explanation would be welcome at the contributing guidelines.

might be better to just include that information in the README

Sure