title: Create new verison of docker image
body: <p>I have built a new docker image using the below command</p>
  <p><code>docker build . -t &lt;username&gt;/&lt;imagename&gt;:&lt;tag&gt;</code></p>
  <p>and pushed it to docker hub. I can see it fine in repo. When I tried to change a file in it and built a new version of image using same docker build, it is getting as a complete new image (when pushed to docker hub repo).</p>
  <p>Can you please suggest what is the right way to create a new version of docker image ?</p>
  <p>Thanks
  Sri.</p>