Feed for upcoming meetups

[rikuwolf]

This is about the list of Angular Finland meetups, with data coming from meetups.com

This feed worked while we has an Express backend on Heroku. Now we have a Firebase backend and we should restore the functionality. Currently we're maintaining the list manually. Not good!

Some notes....

• convert the ExpressJS controllers into Firebase functions [using these models](check the overall logic here: https://github.com/AngularFI/angular-fi/blob/master/src/models/meetup.model.ts)
• REST services and in particular the events service
• Remove Redis - not needed after we migrated to Firebase
• Secure storage for the meetup.com API key (held in meetup.com by Angular Finland's meetup organisers) so that it can be ready by the Firebase function - check this article on storing API keys for Firebase - store as an environment variable in Firebase?