Dockerfile

FROM node:latest
#Pulling from Node.js because our code is written in Node. You can use any version, but in this case, since it's just CRUD, we should be safe with latest

WORKDIR /usr/src/app
#Working Directory inside the "Docker Engine" - something like a virtual computer path that we're making right now because that's how Docker works.

COPY package*.json /usr/src/app/
#Copying all our package files (Package-lock and Package, hence the wildcard * and then .json into the workdir)

RUN npm install 
#Installing the dependencies inside the package files

COPY . /usr/src/app/
#Copying ALL the files (hence the wild card ".") into the working directory. 

EXPOSE 8080 1337
#Exposing a port, which is 8080 and 1337, for apps to connect to. It's basically listening to the exposed port for any incoming traffic.

ENV PORT 8080
CMD ["npm", "run", "dev"]
#means that when a container is started from the image built from that Dockerfile, it will automatically start a development server for a Node.js 
#application by running the dev script defined in the package.json file. This is what Bing AI said.