add ca service

bin/services/ca/app.rb

@@ -0,0 +1,12 @@
+require "roda"
+
+class App < Roda
+  # automatically sets application/json and encodes Ruby objects
+  plugin :json
+
+  route do |r|
+    r.get "hello" do
+      { message: "world" }
+    end
+  end
+end