title: how to commit and push in libgit2sharp
body: <p>I just downloaded the nugget package for libgit2sharp. 
  I am finding it difficult to do even basic operations.</p>
  
  <p>I have an existing git repo (both remote and local). I just need to commit new changes when it occurs and push it to the remote.</p>
  
  <p>I have the code below to explain what I did.</p>
  
  <pre class="lang-cs prettyprint-override"><code>string path = @"working direcory path(local)";
  Repository repo = new Repository(path);
  repo.Commit("commit done for ...");
  
  Remote remote = repo.Network.Remotes["origin"];          
  var credentials = new UsernamePasswordCredentials {Username = "*******", Password = "******"};
  var options = new PushOptions();
  options.Credentials = credentials;
  var pushRefSpec = @"refs/heads/master";                      
  repo.Network.Push(remote, pushRefSpec, options, null, "push done...");
  </code></pre>
  
  <p>Where should I specify remote url's ? also is this the right way of doing these operations(commit &amp; push)?</p>
  
  <p>Thanks</p>