Add 2021 day 2 community solution - Rui Alves

Author: xRuiAlves

docs/puzzles/day2.md

@@ -197,5 +197,6 @@ You can replace the content of the `input/day2` file with your own input from [a
 - [Solution](https://github.com/philipschwarz/advent-of-code-2021-scala/tree/master/src/main/scala/day2) by [@philip_schwarz](https://twitter.com/philip_schwarz)
 - [Solution](https://github.com/FlorianCassayre/AdventOfCode-2021/blob/master/src/main/scala/adventofcode/solutions/Day02.scala) of [@FlorianCassayre](https://github.com/FlorianCassayre).
 - [Solution](https://github.com/Jannyboy11/AdventOfCode2021/blob/main/src/main/scala/day02/Day02.scala) of [Jan Boerman](https://twitter.com/JanBoerman95).
+- [Solution](https://github.com/xRuiAlves/advent-of-code-2021/tree/master/src/main/scala/rui/aoc/year2021/day2) by [Rui Alves](https://github.com/xRuiAlves/)
 
 Share your solution to the Scala community by editing this page.