After reading proper section of GitHub Help I got completely lost. It says:
This file can be committed into the repository, thus sharing the rule list with any other users that clone the repository.
Up until now, people I've been talking to about Git were telling me that ".gitingore
file must be committed or else its rules won't work!"
Every Git begginer's question: "Why .gitignore
rules are not applied?"
Could be answered with a simple: "Did you commit it?".
And now, here comes the GitHub Help saying, that this file can be commited, but it isn't necessary