added Fork Project document

doc/gitlab-basics/README.md

@@ -15,3 +15,5 @@ Step-by-step guides on the basics of working with Git and GitLab.
 * [Create a group](create-group.md)
 
 * [Create a branch](create-branch.md)
+
+* [Fork a project](fork-project.md)

doc/gitlab-basics/create-branch.md

 # How to create a branch
 
 A branch is an independent line of development.
+
 New commits are recorded in the history for the current branch, which results in taking the source from someone’s repository (the place where the history of your work is stored) at certain point in time, and apply your own changes to it in the history of the project.
 
 To add changes to your GitLab project, you should create a branch. You can do it in your [shell](basic-git-commands.md) or in GitLab.

doc/gitlab-basics/fork-project.md

+# How to fork a project
+
+A fork is a copy of an original repository that you can put somewhere else
+or where you can experiment and apply changes that you can later decide if
+publishing or not, without affecting your original project.
+
+It takes just a few steps to fork a project in GitLab.
+
+Sign in to [gitlab.com](https://gitlab.com).
+
+Select a project on the right side of your screen:
+
+![Select a project](basicsimages/select_project.png)
+
+Click on the "fork" button on the right side of your screen:
+
+![Fork](simple_guide_images/fork.png)
+
+Click on the user or group to where you'd like to add the forked project.