Commented the function get_object_by_code

- Once we have a code which relates to an entity we should have a way
to retrieve the correct object (plain python object) related to the
model.
Implemented document creation for Content

- On Question add and delete documents can be created or deleted from
search index
- We have one search index: question_content
- In the future we might have others, I am not sure about using one or
many indexes for executing queries.
Implemented the first version of the search -- for content only