title: Docker create network should ignore existing network
body: <p>My docker containers are running in a local network, called my_local_network. To assure the network exists, every build script starts with:</p>
  
  <pre><code>docker network create --driver bridge my_local_network
  </code></pre>
  
  <p>This works fine. If the network does not exist, it is created, if not, nothing happens. Except for the error message:</p>
  
  <pre><code>Error response from daemon: network with name my_local_network already exists
  </code></pre>
  
  <p>Is there a way to tell docker only to create the network if it doesn't exist?</p>