Connect 5 consecutive pieces in a straight line to win.

message State{
  // Required field to indicate the player who should be making the next move
  // Values = 0 or 1
  int32 player_turn_idx = 1;

/*
  Array of size 225 initialized to -1, representing an empty 15 by 15 board.
  The values of board can be -1, 0, or 1. 
  Placing a piece in index x will set the value of board[x] to the player's index.
  Array is row major order: index 0 is top left, index 14 is top right, index 210 is 
  bottom left, and index 224 is bottom right.
*/
  repeated int32 board = 2;
}
