The bug was in the strange behaviour of sql functions. The return value is presented in a table with strange column name. So I have just renamed it to `res`.

Also renamed AddDiscipline to Discipline_Create

if there are no errors:

"response": {
   *some data*
}

else:

"error": {
   "code": 23,
   "message": "Invalid argument"
}

This reverts commit 115f3a1e.