Merge pull request #4039 from vector-im/new-guest-access

New guest access

config.sample.json

@@ -11,6 +11,7 @@
             "matrix.org"
         ]
     },
+    "welcomeUserId": "@riot-bot:matrix.org",
     "piwik": {
         "url": "https://piwik.riot.im/",
         "siteId": 1

package.json

@@ -77,7 +77,8 @@
     "react-gemini-scrollbar": "matrix-org/react-gemini-scrollbar#5e97aef",
     "sanitize-html": "^1.11.1",
     "ua-parser-js": "^0.7.10",
-    "url": "^0.11.0"
+    "url": "^0.11.0",
+    "velocity-vector": "vector-im/velocity#059e3b2"
   },
   "devDependencies": {
     "autoprefixer": "^6.6.0",