feat: get legal moves via move_types from piece for board

lib/board.rb

@@ -14,10 +14,16 @@ def get(position)
   end
 
   def place(piece, position)
-    position = Position.parse(position) if position.is_a? String
     get(position).piece = piece
   end
 
+  def legal_moves_for(position)
+    piece = get(position).piece
+    piece.move_types.map do |type|
+      type.new(self, position).legal_moves
+    end
+  end
+
   private
 
   def create_fields

test/piece/rook_test.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require "minitest/autorun"
+
+class Piece
+  class RookTest < Minitest::Test
+    def test_rook_can_move_horizontally
+      board = Board.new
+      board.place(Rook.new, "A1")
+      assert_includes board.legal_moves_for("A1"), Position.parse("H8")
+    end
+  end
+end