Tests are slow on Windows 10

[deklanw]

The tests are significantly slower on Windows (10 at least).

I was hesitant on making pull requests for this project until I got this resolved. Turns out to be something related to IPv6. More info here:
Automattic/mongoose#6566 (comment)

pensieve-api/mongoose/config/database.js

Line 8 in e4e9c16

mongoose.connect(config.database.uri);

Just changing the line to
mongoose.connect(config.database.uri, { family: 4 });
works. I don't think it has any unintended consequences, either. Unless the server needs to use IPv6 for some reason?