Triangle solution

Please look at file triangle_facts.rb for solution of the Triangle Facts exercise.
Passing an empty string to `puts` is unnecessary, you could just call the method. Better yet, use string interpolation on the previous call to `puts` and pass a second argument thus:
```ruby
puts "some stuff #{ some_method }", "\n"
```

You can even do it with a single argument, though you have to put two newlines in to defeat `puts` auto-newline behavior:
```ruby
puts "some stuff #{ some_method }\n\n"
```