This code corresponding to the Ignite, Trilha Elixir lab.
The project simulates the sum of the numbers like a calculator.
$ cd course-rocketseat-elixir/chapter-i/module-1/sum_list
$ mix compile
$ mix test
$ mix test --cover
$ iex -S mix
# sum list
iex> SumList.call([1, 2, 3])