add twister markdown support

src/public/css/template/default/common.css

@@ -27,6 +27,13 @@ textarea {
   border: 0;
 }
 
+samp {
+  background: #777;
+  padding: 2px 4px;
+  color: #fff;
+  font-size: 11px;
+}
+
 /* backgrounds */
 .bg-logo-1 {
   background-image: url('/css/template/default/image/logo-1.png');

src/system/helper/format.php

@@ -48,6 +48,12 @@ class Format {
 
   public static function post(string $text) {
 
+    $text = preg_replace("|\*(.*?)\*|i", "<b>$1</b>", $text);
+    $text = preg_replace("|\~(.*?)\~|i", "<i>$1</i>", $text);
+    $text = preg_replace("|\_(.*?)\_|i", "<u>$1</u>", $text);
+    $text = preg_replace("|\-(.*?)\-|i", "<s>$1</s>", $text);
+    $text = preg_replace("|\`(.*?)\`|i", "<samp>$1</samp>", $text);
+
     $text = preg_replace("|@([a-zA-Z0-9_]+)|i", "<a href=\"people/$1\">@$1</a>", $text);
     $text = preg_replace("|((https?://)+([\d\w\.-]+\.[\w\.]{2,6})[^\s\]\[\<\>]*/?)|i", "<a href=\"$1\" target=\"_blank\">$3</a>", $text);
     $text = nl2br($text);