title: add user to mongodb via python
body: <p>I want to be able to add users to MongoDB so that we can automate MongoDB installs with authentication already baked in. I can successfully add users using pymongo that are read only or are dbOwner by doing this:</p>
  
  <pre><code>from pymongo import MongoClient
  
  client = MongoClient('localhost:27017')   
  client.admin.authenticate('siteRootAdmin', 'Test123')
  client.testdb.add_user('newTestUser', 'Test123', True)
  </code></pre>
  
  <p>but when I do this following code block to specify roles, it fails: </p>
  
  <pre><code>from pymongo import MongoClient
  
  client = MongoClient('localhost:27017')
  client.admin.authenticate('siteRootAdmin', 'Test123')
  client.testdb.add_user('newTestUser', 'Test123', False, 'readWrite')
  </code></pre>
  
  <p>with the error:</p>
  
  <pre><code>line 10, in &lt;module&gt;
      client.admin.add_user('newTestUser', 'Test123', False, 'readWrite')
  TypeError: add_user() takes at most 4 arguments (5 given)
  </code></pre>
  
  <p>In the docs it implies that you are able to have optional fields for the user document such as other roles. Has anyone been able to set these correctly? Namely, I want to have readWrite service accounts that can add data to collections but don't have full dbOwner privileges.</p>