yarn added

Author: zonayedpca

package.json

@@ -5,7 +5,7 @@
     "main": "app.js",
     "author": "Zonayed Ahmed",
     "scripts": {
-        "preinstall": "cd client && npm install",
+        "preinstall": "cd client && yarn install",
         "test-client": "npm run test --prefix client -- --watchAll=false",
         "test": "npm run test-client",
         "client": "npm start --prefix client",