Update README.md

Author: lganzzzo

client-mbedtls/README.md

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+# secure websocket client with mbedtls
+
+Simple example of the secure websocket client. Built with oat++ (AKA oatpp) web framework.  
+TLS backend - MbedTLS.
+
+See more:
+
+- [Oat++ Website](https://oatpp.io/)
+- [Oat++ Github Repository](https://github.com/oatpp/oatpp)
+- [Get Started With Oat++](https://oatpp.io/docs/start)
+
+## Overview
+
+### Project layout
+
+```
+|- CMakeLists.txt                         // projects CMakeLists.txt
+|- src/
+|    |
+|    |- WSListener.hpp                    // WebSocket listeners are defined here
+|    |- App.cpp                           // main() is here
+|
+|- utility/install-oatpp-modules.sh       // utility script to install required oatpp-modules.  
+```
+
+## Build and Run
+
+### Using CMake
+
+**Requires** 
+- MbedTLS installed - see [install mbedtls](#install-mbedtls). 
+- [oatpp](https://github.com/oatpp/oatpp), [oatpp-websocket](https://github.com/oatpp/oatpp-websocket), 
+and [oatpp-mbedtls](https://github.com/oatpp/oatpp-mbedtls) modules installed. You may run `utility/install-oatpp-modules.sh` 
+script to install required oatpp modules.
+
+```
+$ mkdir build && cd build
+$ cmake ..
+$ make 
+$ ./websocket-client-mbedtls-exe       # - run application.
+```
+
+## Install MbedTLS
+
+```bash
+git clone -b 'mbedtls-2.16.1' --single-branch --depth 1 --recurse-submodules https://github.com/ARMmbed/mbedtls
+
+cd mbedtls
+mkdir build && cd build
+
+cmake ..
+make install
+```