title: Git cannot merge unrelated branches
body: <p>I am in some software project in which we store our code on GitHub. There's a repo with master and development branch. I was on my laptop without an internet connection and I wanted to start working on another feature, so I did the following:</p>
  
  <pre><code>git init
  git remote add origin git://repo_adress
  git checkout -b webapp &lt;- created a new branch
  </code></pre>
  
  <p>I've added few files, folders, etc.</p>
  
  <p>Then I did:</p>
  
  <pre><code>git add .
  git commit -m "something"
  git push origin webapp
  </code></pre>
  
  <p>I checked on GitHub, now there are 3 branches. I want to merge webapp to development (there will be no conflicts, I work in a separate folder). Unfortunately when I tried to <code>git pull</code>, this happened:</p>
  
  <pre><code> * [new branch]      development -&gt; origin/development
   * [new branch]      master      -&gt; origin/master
  There is no tracking information for the current branch.
  Please specify which branch you want to merge with.
  See git-pull(1) for details.
  </code></pre>
  
  <p>Now when I go with <code>git pull origin development</code>, this shows up:</p>
  
  <pre><code>From github.com:repo_address
   * branch            development -&gt; FETCH_HEAD
  fatal: refusing to merge unrelated histories
  </code></pre>
  
  <p>What can I do now? Should I rebase?</p>