New functionality regarding the app and the file 'Additional functions estimation_pc_lessons 06.11.2018 (v3)'. Functions of interest:
1. Attaching profile/background picture, text if left blank when registering
3. Welcome mail with the videos of functions. Message in the Lessons inbox too.
4. Change the text in the receipt when a user receives money
5. Get rid of the 5Mb file limit and make it unlimited