Add .sys command

ubot.py

@@ -101,6 +101,15 @@ async def edit(event):
 			rpl += '`' + out + '`\n'
 			await event.edit(rpl)
 	
+	if '.sys' in msg:
+		mem = os.popen('free -m').readlines()[1].split()[2]
+		disk = os.popen('df -h /').readlines()[1].split()[2]
+
+		rpl  = '**System usage stats:**\n'
+		rpl += '**Memory:** ' + mem + 'M\n'
+		rpl += '**Disk:** ' + disk + '\n'
+		await event.edit(rpl)
+
 	if '.sauce' in msg:
 		rpl = 'Sauce: [ghnou/ubot](https://git.ghnou.su/ghnou/ubot)'
 		await event.edit(rpl)