Lua translation!

Several solutions (including mine / ruby at least, may be needed for JS too) are stripping the output. Meaning that any input with "unlucky placed whitespace" will make fail these solutions.

=> need some more edge cases.

The use of the instance variable in this kata is poor design, which adds unnecessary coupling between consecutive calls to the methods of the class.

It would be better if this were simply 2 class methods that took a string to encode/decode

class SimpleTransposition 
    def self.encode(string)
    end
    
    def self.decode(string)
    end
end

It would be better to have more hinted, what should be stored in instance variables. Tests are not full and everybody can think of different flow