Enable some extentions for the Markdown syntax

Enable the strikethrough, tagfilter, tasklist and autolink extensions
from the GFM spec.

src/list.rs

@@ -8,8 +8,13 @@ use std::time::SystemTime;
 
 /// Converts raw string data (in Markdown format) to HTML
 pub fn data_to_html(data: &String) -> String {
-    comrak::markdown_to_html(data,
-        &comrak::ComrakOptions::default())
+    let mut options = comrak::ComrakOptions::default();
+    options.ext_strikethrough = true;
+    options.ext_tagfilter = true;
+    options.ext_autolink = true;
+    options.ext_tasklist = true;
+
+    comrak::markdown_to_html(data, &options)
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize)]