title: Merging dataframes based on date range
body: <p>I have two pandas dataframes: one (<code>df1</code>) with three columns (<code>StartDate</code>, <code>EndDate</code>, and <code>ID</code>) and a second (<code>df2</code>) with a Date. I want to merge <code>df1</code> and <code>df2</code> based on df2.Date between <code>df1.StartDate</code> and <code>df2.EndDate</code>. </p>
  
  <p>Each date range in <code>df1</code> is unique and doesn't overlap with any of the other rows in the dataframe.</p>
  
  <p>Dates are formatted <code>YYYY-MM-DD</code>.</p>