chatting app documenation

Setup Server "Mongodb ,Nodejs and other tools" 1. setup Server steps Setup Mongodb :   Step 1- Initialation :          if you already have installed the mongodb and you remove it make sure your run this command :               First, remove any existing repository file for MongoDB.     sudo rm /etc/apt/sources.list.d/mongodb*.list       Next, add the key: ( without the key, the repository will not load )        sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv E52529D4        Now, create a new MongoDB repository list file:        sudo bash -c 'echo "deb http://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/4.0 multiverse" > /etc/apt/sources.list.d/mongodb-org-4.0.list'   Step 2 - Update the repository :     update the repository with the apt command:   sudo apt-...