Fixed #908 -- Enable account notification for inviting friend to OH.

[ArcTanSusan]

Resolves https://openhatch.org/bugs/issue908. Feel free to code review and make suggestions for improvement.

New notification message after the Welcome to OH email has been sent to a friend (or enemy):

[coveralls]

Coverage remained the same when pulling f0fc3e7 on onceuponatimeforever:908 into 94beb63 on openhatch:master.

[jwm]

Merged - thanks, Susan!

I also made a couple small style improvements after merging your commit - you can see them at d35c2bc . In particular, .get() returns None by default, so it's nice to omit the default value, and I added a comma after the last dict item so future changes only have to change the line(s) they're adding or removing and don't need to worry about dealing with the comma.

[paulproteus]

Hey @jwm and @onceuponatimeforever,

Thanks for writing & reviewing!

A meta-remark here: it seems like these bits of code style feedback could be automated, to decrease the latency with which contributors get the feedback.

One tool we could use for that is https://github.com/justinabrahms/imhotep ; we'd have to host it somewhere. Perhaps on vm3.openhatch.org, which is where our Jenkins is, or perhaps on Heroku.

I've filed https://openhatch.org/bugs/issue930 accordingly!