step 1:
	 run service with 1 parameter AUTHORIZATION_CODE

step 2:
	POST login.teithe.gr/token
	headers:
		Content-Type: application/x-www-form-urlencoded
	body:
		client_id: MY_CLIENT_ID
		client_secret: MY_CLIENT_SECRET
		grant_type:authorization_code
		code: MY_AUTHORIZATION_CODE

	request success
		- store REFRESH_TOKEN
		- store ACCESS_TOKEN
	request failed
		possible email for notification and kill service

step 3:
	create methods
		- refresh token
			POST login.teithe.gr/token
			headers:
				Content-Type: application/x-www-form-urlencoded
			body:
				client_id: MY_CLIENT_ID
				client_secret: MY_CLIENT_SECRET
				grant_type:refresh_token
				code: REFRESH_TOKEN

            request success
                - store REFRESH_TOKEN
                - store ACCESS_TOKEN
            request failed
                possible email for notification and kill service

		- load announcments
            GET api.it.teithe.gr/announcements
            headers:
                x-access-token: ACCESS_TOKEN
                Content-Type:application/json

            request success
                - if previews list size < new list
                    find new announcments
                        send notification
                        override list with new list
            request failed
                if code 401
                    possible email for notification and kill service
                else
                    ignore

		- send notification(id, about, category, name, title)
            post firebase service