title: Applying slice() to a tbl
body: <p>In dplyr, when I use the function slice() on a tbl (postgres database), I get the following error:</p>
  
  <pre><code>Error in UseMethod("slice_") : no applicable method for 'slice_' applied to an object of class "c('tbl_dbi', 'tbl_sql', 'tbl_lazy', 'tbl')"
  </code></pre>
  
  <p>I don't want to convert my tbl to a data frame since it's large. Is there a way that I can apply slice to tbl or an alternative command?</p>