Merge branch 'How_to_Reset_your_root_password' into 'master'

How to reset your root password

Added link and file correctly on Security doc.

Please review to make sure it's correct.

See merge request !1811

doc/security/README.md

@@ -4,3 +4,4 @@
 - [Rack attack](rack_attack.md)
 - [Web Hooks and insecure internal web services](webhooks.md)
 - [Information exclusivity](information_exclusivity.md)
+- [Reset your root password](reset_root_password.md)
\ No newline at end of file

doc/security/reset_root_password.md

+# How to reset your root password
+
+Log into your server with root privileges. Then start a Ruby on Rails console.
+
+Start the console with this command:
+
+```bash
+gitlab-rails console production
+```
+
+Wait until the console has loaded.
+
+There are multiple ways to find your user. You can search for email or username.
+
+```bash
+user = User.where(id: 1).first
+```
+
+or
+
+```bash
+user = User.find_by(email: 'admin@local.host')
+```
+
+Now you can change your password:
+
+```bash
+user.password = 'secret_pass'
+user.password_confirmation = 'secret_pass'
+```
+
+It's important that you change both password and password_confirmation to make it work.
+
+Don't forget to save the changes.
+
+```bash
+user.save!
+```
+
+Exit the console and try to login with your new password.
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