Adding application/jrd+json webfinger resource

app/views/xrd/webfinger.json.rabl

@@ -0,0 +1,16 @@
+object @account
+
+node(:subject) { @canonical_account_uri }
+
+node(:aliases) do
+  [TagManager.instance.url_for(@account)]
+end
+
+node(:links) do
+  [
+    { rel: 'http://webfinger.net/rel/profile-page', type: 'text/html', href: TagManager.instance.url_for(@account) },
+    { rel: 'http://schemas.google.com/g/2010#updates-from', type: 'application/atom+xml', href: account_url(@account, format: 'atom') },
+    { rel: 'salmon', href: api_salmon_url(@account.id) },
+    { rel: 'magic-public-key', href: "data:application/magic-public-key,#{@magic_key}" }
+  ]
+end