title: How to sync all branches of two repositories (one in github and one in gitlab) preventing merge conflicts?
body: <p>Repository X.git is in gitlab with all development artifacts and respective branches
  I create Y.git in github using the following approach
  In a common server I do a mirror of gitlab</p>
  
  <pre><code>git clone --mirror http://gitlabserverdomain/user/X.git
  cd X.git
  git remote add githubrepoalias https://githubserverdomain/Y.git
  git push -f --tags githubrepoalias refs/heads/*:refs/heads/*
  </code></pre>
  
  <p>Now I want to enable users to use either repositories for sometime and would like to sync either commits</p>
  
  <p>These commits should not cause merge conflicts.</p>
  
  <p>How do I do achieve the objective?</p>