Registers stix-ttp taxonomy in MANIFEST.json.

MANIFEST.json

@@ -159,6 +159,11 @@
       "description": "The Targeted Threat Index is a metric for assigning an overall threat ranking score to email messages that deliver malware to a victim’s computer. The TTI metric was first introduced at SecTor 2013 by Seth Hardy as part of the talk “RATastrophe: Monitoring a Malware Menagerie” along with Katie Kleemola and Greg Wiseman.",
       "name": "targeted-threat-index",
       "version": 1
+    },
+    {
+      "description": "Representation of the behavior or modus operandi of cyber adversaries (a.k.a TTP) as normalized in STIX",
+      "name": "stix-ttp",
+      "version": 1
     }
   ]
 }