[Keyboard] Add Contender (#15403)

Co-authored-by: Ryan <fauxpark@gmail.com>

keyboards/contender/contender.h

@@ -0,0 +1,43 @@
+/* Copyright 2020 sotoba
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "quantum.h"
+
+/* This is a shortcut to help you visually see your layout.
+ *
+ * The first section contains all of the arguments representing the physical
+ * layout of the board and position of the keys.
+ *
+ * The second converts the arguments into a two-dimensional array which
+ * represents the switch matrix.
+ */
+#define LAYOUT( \
+      k00, k01, k02, k03, \
+      k10, k11, k12, k13, \
+      k20, k21, k22, k23, \
+    k30, k31, k32, k33, k34, \
+    k40, k41, k42, k43, k44, \
+    k50, k51, k52, k53 \
+) { \
+    { KC_NO, k00, k01, k02, k03 }, \
+    { KC_NO, k10, k11, k12, k13 }, \
+    { KC_NO, k20, k21, k22, k23 }, \
+    { k30, k31, k32, k33, k34 }, \
+    { k40, k41, k42, k43, k44 }, \
+    { k50, k51, k52, k53, KC_NO } \
+}