Add gdbinit config

.gdbinit

@@ -0,0 +1,29 @@
+define bmconnect
+	if $argc < 1 || $argc > 2
+		help bmconnect
+	else
+		target extended-remote $arg0
+		if $argc == 2
+			monitor $arg1 enable
+		end
+			monitor swdp_scan
+		attach 1
+	end
+end
+
+document bmconnect
+  Attach to the Black Magic Probe at the given serial port/device.
+    bmconnect PORT [tpwr]
+  Specify PORT as COMx in Microsoft Windows or as /dev/ttyACMx in Linux.
+  If the second parameter is set as "tpwr", the power-sense pin is driven to
+  3.3V
+end
+
+# Load .gdbinit files from current dir
+set auto-load local-gdbinit
+
+# save command history
+set history save on
+set history size 10000
+set history remove-duplicates unlimited
+set history filename ~/.gdb_history