Actually helpful registration errors

.ruby-version

@@ -1 +1 @@
-2.2.3
+2.3.1

app/controllers/api/abstract_controller.rb

@@ -20,6 +20,11 @@ module Api
             'schedule_id, sequence_id, id, etc..', 400
     end
 
+
+    rescue_from Mongoid::Errors::Validations do |exc|
+      render json: {error: exc.summary}, status: 422
+    end
+
 private
 
     def current_device