Easy Newslettering

added option to add in a second calendar (Tentative) to make another email campaign
actually doing the same transition on Eventum right now (https://github.com/danrschlosser/eventum/pull/75/files).

The idea is to avoid hardcoding any credentials in your code ever. A popular way of doing this is to store you credentials in a small bash script that adds them to the environment when you `source your_script.sh`. Then when you execute your project, it pulls the credentials from the environment.

Then you just need to be sure to gitignore your `settings.sh` file so that you don't commit your passwords.

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This is generally a bit easier to manage since you won't need to delete those 2 lines every time you commit, instead you're just ignoring the file with the sensitive information