Update Readme.md file accroding to markdown template

Closes #3343295

README.md

-CONTENTS OF THIS FILE
----------------------
- 
- * Introduction
- * Installation
- * Configuration
- * Maintainers
-
-INTRODUCTION
-------------
-
-This is a very basic module which provide a new option in vocabulary 
-creation/edition form to enforce it to be flat.
-As a developer, I faced some situation where the vocabulary 
-was supposed to be flat and development have been done based 
-on that assumption. Later, a contributor creates a new term 
-using the parent field (hierarchical vocabulary). 
-It causes issue on the front-end or at least 
-it is confusing for the contributor.
-This module should avoid the situation by 
-removing the possibility to create nested terms.
-
-Alter the term creation/edition for to be sure it is impossible 
-to select a parent.
-
-Alter the term overview page to be sure it is impossible to 
-create a nested vocabulary.
-
-The Drupal 7 version of the module has some additional features:
- * Drush integration to flatten a vocabulary
- * Confirmation step on vocabulary edition form if the form is 
-flagged to be flatten but contains nested terms.
+# Flat taxonomy
+
+This is a very basic module which provide a new option in vocabulary
+creation/edition form to enforce it to be flat. As a developer, I faced some
+situation where the vocabulary was supposed to be flat and development have been
+done based on that assumption. Later, a contributor creates a new term using the
+parent field (hierarchical vocabulary). It causes issue on the front-end or at
+least it is confusing for the contributor. This module should avoid the
+situation by removing the possibility to create nested terms.
+
+Alter the term creation/edition for to be sure it is impossible to select a
+parent.
+
+Alter the term overview page to be sure it is impossible to create a nested
+vocabulary.
+
+The Drupal version of the module has some additional features:
+- Drush integration to flatten a vocabulary.
+- Confirmation step on vocabulary edition form if the form is flagged to be
+  flatten but contains nested terms.
 
 Any new feature to be added to the module is welcomed ;-)
 
- * For a full description of the module, visit the project page:
-   https://www.drupal.org/project/flat_taxonomy
+For a full description of the module, visit the
+[project page](https://www.drupal.org/project/flat_taxonomy).
+
+To submit bug reports and feature suggestions, or track changes in the
+[issue queue](https://www.drupal.org/project/issues/flat_taxonomy).
+
+
+## Table of contents
+
+- Requirements
+- Installation
+- Configuration
+- Maintainers
+
+
+## Requirements
+
+This module requires no modules outside of Drupal core.
+
+
+## Installation
+
+Install as you would normally install a contributed Drupal module. For further
+information, see
+[Installing Drupal Modules](https://www.drupal.org/docs/extending-drupal/installing-drupal-modules).
+
 
- * To submit bug reports and feature suggestions, or to track changes:
-   https://www.drupal.org/project/issues/flat_taxonomy
+## Configuration
 
-INSTALLATION
-------------
+1. Enable the module at Administration > Extend.
+2. When creating new texonomy a new checkbox to be appearing to the bottom side.
+3. Checking up the checkbox should avoid the situation by removing the
+   possibility to create nested terms.
 
- * Install as you would normally install a contributed Drupal module. Visit
-   https://www.drupal.org/node/1897420 for further information.
 
-MAINTAINERS
------------
+## Maintainers
 
- * vbouchet - https://www.drupal.org/u/vbouchet
+- Vincent Bouchet - [vbouchet](https://www.drupal.org/u/vbouchet)