changes npm install to npm ci

Author: tonyqiu123

README.md

@@ -17,10 +17,10 @@ git clone git@github.com:uwblueprint/mississippi-farm-to-school-network.git
 Create .env files in both backend and frontend folders (empty for now)
 
 `cd backend`
-`npm install`
+`npm ci`
 
 `cd ../frontend`
-`npm install`
+`npm ci`
 
 Ensure Docker Daemon is running.