Setting up preliminary "detailed" routes in the UI, new API end-point for fetching status context

app/views/api/statuses/context.rabl

@@ -0,0 +1,13 @@
+object false
+
+node :ancestors do
+  @ancestors.map do |status|
+    partial('api/statuses/show', object: status)
+  end
+end
+
+node :descendants do
+  @descendants.map do |status|
+    partial('api/statuses/show', object: status)
+  end
+end