Adds Python snippet for metadata refreshing

Author: liancheng

docs/sql-programming-guide.md

@@ -1036,6 +1036,15 @@ for (teenName in collect(teenNames)) {
 
 </div>
 
+<div data-lang="python"  markdown="1">
+
+{% highlight python %}
+# sqlContext is an existing HiveContext
+sqlContext.refreshTable("my_table")
+{% endhighlight %}
+
+</div>
+
 <div data-lang="sql"  markdown="1">
 
 {% highlight sql %}