add display: flex

[jgillich]

I'm not sure how to name this one, since flex is obviously taken.

ref #13

[lukewestby]

this is the case for a couple other property keys/values as well, like top and bottom. can you take a look at https://github.com/rtfeldman/elm-css/blob/master/src/Css.elm#L521-L529 as a starting point for how this was handled for those?

[jgillich]

I've looked into it, but this is a bit much for me right now; as mentioned in the original issue, I'm just getting started with Elm. Will revisit this in a couple of days/weeks.

[lukewestby]

sounds good! this is definitely a peculiarity of css that feels odd to represent in elm. anyone you can find on this repo or in the elm slack channel or elm-discuss mailing list would be happy to help out as you're working on it!

[rtfeldman]

I added displayFlex to implement this. Thanks!