.gitignore not ignoring folder

Question

I have a project in Laravel and I have forum in public directory which I don't want to push it to repository, so I write in .gitignore:

### Laravel ###
vendor/
node_modules/

# Laravel 5 & Lumen specific
bootstrap/cache/
.env.*.php
.env.php
.env

# SMF
public/forum/

# Rocketeer PHP task runner and deployment package. https://github.com/rocketeers/rocketeer
.rocketeer/

However, the entry still appears in Git status
Here is my tree with it:
+...
+ public
++ forum
+++...
+...
Where is the problem?

Directory structure

Git status

Answer 1

In .gitignore add

public/forum

Run

git rm --cached -r public/forum

Answer 2

The problem is that this folder is already in your index (you committed it at an earlier moment). Changes to files in the index will always be in "git status". Only new files in that folder will be ignored.

To fix it. See my answer on https://stackoverflow.com/a/38304114/2274140