* **Create:** First collaboration request has to be created (user)
  * **Finalize permanently:** With state xtwf_request_finish_finally collaboration is permanently finalized, i.e. can not be renewed again
  * **Subscribe/Unsubscribe:** User can subscribe / unsubscribe while collaboration is running, i.e. created and not permanently finalized
  * **Admin:** .....
  * **Dev:** ....

====== List of states ======
  - Type: request
    - xtwf_request_collaborate: **Request collaboration**
    - xtwf_request_renew: **Request for renew**
    - xtwf_request_finish_finally: **Request for finish finally**
  - Type: competition
    - xtwf_competition: **Competition**
  - Type: discussion
    - xtwf_discussion: **Discussion**
  - Type: finished
    - xtwf_finished_renewable: **Finished renewable**
    - xtwf_finished_finally: **Finished finally**
  - Type: content_collect
    - xtwf_collect_content: **Collect contents**
    - xtwf_collect_keynotes: **Collect keynotes**
    - xtwf_collect_questions: **Collect questions**
    - xtwf_free_contributions: **Free contributions** ????
  - Type: content_rating
    - xtwf_rating_content: **Rating contents**
    - xtwf_rating_keynotes: **Rating keynotes**
    - xtwf_rating_questions: **Rating questions**
  - Type: run_workflow
    - xtwf_run_leaf:leaf//$idx// **RunLeaf//@idx//** - //for ($idx = 1; $idx <= $number_leafs; $idx++)//
    - xtwf_run_twig:twig//$idx// **RunTwig//@idx//** - //for ($idx = 1; $idx <= $number_twigs; $idx++)//