title: difference between context.xml and server.xml?
body: <p>what is the difference between <code>context.xml</code> of Tomcat and <code>server.xml</code> of Tomcat ? If I want to add a tag like :</p>
  
  <pre><code>    &lt;Resource name="jdbc/MyDs" auth="Container" type="javax.sql.DataSource"
       driverClassName="org.apache.derby.jdbc.ClientDriver"
       url="jdbc:derby://localhost:1527/my_database;create=true"
       username="me" password="me" maxActive="20" maxIdle="10" maxWait="-1" /&gt;
  </code></pre>
  
  <p>where should I add it ?</p>