What is the best method to write user "log files" of an android application to a file in a remote server or a table in a remote database?

What is the best method to write user "log files" of an android
application to a file in a remote server or a table in a remote database?

I am creating a multi user android application and it is connected to a
php web service in a remote server and to a remote database via that web
service. I want to keep a track of all the important activities done by
the users. For an example if a user logged in to the app and changed his
profile details and then logged out, a brief description of what he has
done should be recorded(with time) somewhere. So then the admin of the
system can see what the users are doing. So I think it is better to use
log cat files and then flush all those data to a unique file in the server
or a table in the database, when the user logs out or exists from his
account. I it is appropriate How to do it?