Connect with MySQL database to receive number of users from every group.

• Add request for get number of users by group and whole.
• Add routing of request users number.

Add consultations parsing from every reffered page in that link.
Convert consultations for JSON in GET-request.

At the moment my Vue.js applications can't to read JSON, that compiled by our API and received from GET request.
This issue will be linked to PR #4.

I think it will work better, when whole consultations described in one JSON response from our API.
Like:

{
                    "teacher": "Gumenjuk, Svetlana",
                    "room": "A 140",
                    "department": "general",
                    "times": {
                        "0": {
                            "weekday": "Monday",
                            "time": "15.55-16.40"
                        }
                    }
                }

Realize /changes and /consultations API request keys like /changes&date=04122020 and /consultations&department=it.
When parameters for isn't defined, request returns full list of information.

Add changes parsing from here.
Convert changes for JSON in GET-request.