lein run runs a default AI vs AI simulation with an empty board.
In repl (lein repl), you can play against the AI with the function player. The game expects you to input the index (0-8) of the square you want to play.
You can simulate AI vs AI with different board states with the play-game -function. The function takes an initial state and starting turn as parameters. State is given with a string, for example: "???xxo?o?" Starting turn is an boolean, true on x's turn.