Adds the 'Beer Song' exercise

[Zureka]

Here's an implementation of the Beer Song exercise. I am still missing the entry in the config.json file, but I'm not sure if there would be much different compared to the implementation in the Ruby track:

    {
      "slug": "beer-song",
      "uuid": "50c34698-7767-42b3-962f-21c735e49787",
      "core": false,
      "unlocked_by": "scrabble-score",
      "difficulty": 3,
      "topics": [
        "loops",
        "strings",
        "text_formatting"
      ]
    },

I would be happy to make any necessary edits. Just let me know!

[Stargator]

@Zureka Can you add a .meta folder that contains a file named version that contains the version number from canonical-data.json?

I'll look over this in a couple of hours.

[Stargator]

@Zureka The config entry you posted above looks good, just place it after scrabble-score.

[Stargator]

Great work, after the changes be sure to run the bin/presubmit.dart file to ensure everything is correct and formatted

[Stargator]

It's looking good, just a couple minor tweaks and I'll be ready to approve it.

[Stargator]

@Zureka, would you feel comfortable squashing the three commits into one? Otherwise, I approve

[Zureka]

@Stargator I just force pushed the squashed commits. Thanks for the thorough review!

I would be willing to add more exercises after this one. I'll take a look at the exercises mentioned in this GitHub Issue to figure out what to implement next.

[Stargator]

@Zureka Feel free to check out #198 or #183 as well, that would be helpful as exercises get updated or new ones created.