title: COPY failed: no source files were specified while docker-compose up
body: <p>Dockerfile for express API is like it:</p>
  
  <pre><code>FROM node:10.15.3
  
  MAINTAINER AshishkrGoyal &lt;ashish.goyal@algoscale.com&gt;
  
  #RUN mkdir -p /usr/src/app
  
  #define working dir
  WORKDIR /usr/src/app
  
  #available package.json, package-lock.json as well
  COPY package*.json ./
  
  #install all dependencies listed in package.json
  RUN npm install
  
  #copy all the source code to working dir
  COPY . .
  
  #mapping of port to docker daemon
  EXPOSE 3000
  
  #command in the form of array
  CMD ["npm", "run", "dev"]
  
  
  </code></pre>
  
  <p>docker-compose.yml is like as shown below:</p>
  
  <pre><code>#specify the docker-compose version
  version: '3.0'
  
  services:
  #specify all the services 
    angular: #it is frontend service container name
      build: public #dockerfile directory
      ports:
        - "4200:4200"
  
    express: #it is backend service container name
      build: server #dockerfile directory
      ports:
        - "3000:3000"
      links:
        - database
  
    database: #it is elastc search service container name
      image: docker.elastic.co/elasticsearch/elasticsearch:7.0.0
      ports:
          - "9200:9200"
  </code></pre>
  
  <p>While running command docker-compose up i am getting following error:
  <strong>ERROR: Service 'express' failed to build: COPY failed: no source files were specified</strong></p>
  
  <p>Please help me in solving this error.</p>
  
  <p>Thanks in advance!!</p>