How to solve the problem with adding a user to the www-data group?

Question

Apache HTTP Server

I'm on ubuntu, installed apache2, php. So far, everything seemed to be working, but when I decided to work with files, it turned out that the server had no rights to the files.
For a long time I studied articles on the Internet, tried many options, but nothing came of it.
Let me explain: I want to add my user to the www-data group in order to access the site. The folder /var/www is recursively owned by www-data

drwxrwx---  6 www-data www-data 4096 Jan 28 21:42 www/

Added a user to the www-data group

grep www-data /etc/group
www-data:x:33:serii

only now, I can not go to the www folder.
I don’t understand here, I added the user to the www-data group, but he was never added

groups 
serii adm cdrom sudo dip plugdev lpadmin sambashare

How to solve my problem, or can someone tell me a working instruction that will provide the user and the server with access to the site?
Thanks in advance.

Answer 1

Make it easier.
Start Apache on your behalf.
In console:
Change variables:

export APACHE_RUN_USER=login
export APACHE_RUN_GROUP=login

And then once I was tormented with these rights and other groups)
Well, about the group, then add like this:
And give rights recursively:
sudo chmod 775 -R /path/to/project