[Keyboard] Add bthlabs/geekpad (#4840)

* Hello, GeekPad!

* Fixed formatting in `README.md`.

keyboards/bthlabs/geekpad/geekpad.h

@@ -0,0 +1,40 @@
+/* Copyright 2019-present Tomek Wójcik <contact@bthlabs.pl>
+ *
+ * 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/>.
+ */
+#ifndef GEEKPAD_H
+#define GEEKPAD_H
+
+#include "quantum.h"
+
+/* This 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, \
+    K10, K11, K12, \
+    K20, K21, K22  \
+) \
+{ \
+    { K00,   K01,   K02 }, \
+    { K10,   K11,   K12 }, \
+    { K20,   K21,   K22 }  \
+}
+
+#endif