title: Adding Time Stamp to a date in R
body: <p>Hi Have 2 columns in a dataframe. Column 1 has Dates like 2017-01-01 and column 2 has time stamp like 1:00 PM.</p>
  
  <p>I need to create another column that combines these 2 information and gives me the 2017-01-01 13:00:00</p>