Undo code removal

Author: tingkai-mai

backend/collaboration/.dockerignore

@@ -0,0 +1,4 @@
+.env
+node_modules/
+dist/
+sample.env

backend/collaboration/Dockerfile

@@ -0,0 +1,13 @@
+FROM node
+
+WORKDIR /app
+
+COPY package*.json ./
+
+RUN npm install
+
+COPY . .
+
+EXPOSE 3001
+
+CMD ["npm", "start"]