Plantuml Support

requirments.txt: Plantuml extension support added for Readthedoc publishing.
building-project-documentation.rst: Prerequisite added for document generation.
README.md: Reference link added for prerequisite.

Signed-off-by: shettygururaj <gururaj.shetty@huawei.com>

README.md

@@ -32,10 +32,7 @@ by simply running:
 make
 ```
 
-For the above command to succeed, the host needs to provide `sphinx-build` and
-the following sphinx extensions:
-* sphinx-tabs (supports tabbed content in the document)
-* sphinxcontrib.plantuml (supports plantuml content)
+For the above command to succeed, ensure all the [prerequisites](https://allscenarios.readthedocs.io/en/latest/building-project-documentation.html) are satisfied.
 
 ## Contributing
 

building-project-documentation.rst

@@ -19,11 +19,29 @@ The |main_project_name| documentation is written in reStructuredText markup
 language (``.rst`` file extension) with Sphinx extensions to generate a
 structured stand-alone website.
 
-To generate the HTML documentation locally, Sphinx must be installed on your
-local system. Also, to build the documentation using the provided ``Makefile``,
-make must also be available on your host.
+Prerequisites
+*************
+To generate the HTML documentation locally, you need to have the following 
+packages pre-installed in your system:
 
-For more details on Sphinx installation, refer `Sphinx Getting Started <https://www.sphinx-doc.org/en/master/usage/quickstart.html>`__.
+* Sphinx (for more details on Sphinx installation, `check Sphinx Getting Started documentation <https://www.sphinx-doc.org/en/master/usage/quickstart.html>`_)
+* The following Sphinx Extensions
+
+   * sphinx-tabs (supports tabbed content in the documentation) 
+   * sphinxcontrib.plantuml (supports plantuml content) 
+
+* Plantuml (supports UML diagrams)
+
+  The method of installing the `plantuml` package is dependent on your Linux 
+  distribution.  For example, on a Ubuntu host, you can install `plantuml` 
+  using the official package repository:
+    
+  .. code-block:: console
+	
+     $ sudo apt-get update -y
+     $ sudo apt-get install -y plantuml
+
+* Make (to build the documentation using the provided Makefile)
 
 Building the documentation
 **************************

requirements.txt

@@ -5,3 +5,4 @@
 six
 recommonmark
 sphinx-tabs
+sphinxcontrib_plantuml