Add Bootstrap To Angular app

// install bootstrap and jquery : 
npm install bootstrap 
npm install jquery 

// update angular.json file like this to use bootstarp and jquery : 
            "styles": [
              "node_modules/bootstrap/dist/css/bootstrap.css",
              "src/styles.css"
            ],
            "scripts": [
              "node_modules/jquery/dist/jquery.js", 
              "node_modules/bootstrap/dist/js/bootstrap.js" 
            ]