code: def feed(input)
        head = @start.to_s
        input.each_char { |symbol| head = @transitions[head][symbol] }
        accept = is_accept_state? head
        resp = {
          input: input,
          accept: accept,
          head: head 
        }
        resp
      end
docs: Runs the input on the machine and returns a Hash describing
   the machine's final state after running.
  
   @param [String] input the string to use as input for the DFA
   @return [Hash] a hash describing the DFA state after running
     * :input [String] the original input string
     * :accept [Boolean] whether or not the DFA accepted the string
     * :head [String] the state which the head is currently on