Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
2018–19 Reading F.C. season
Table title:
In
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Date </th><th colspan=1 rowspan=1 > Position </th><th colspan=1 rowspan=1 > Nationality </th><th colspan=1 rowspan=1 > Name </th><th colspan=1 rowspan=1 > From </th><th colspan=1 rowspan=1 > Fee </th><th colspan=1 rowspan=1 > Ref. </th></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 17 May 2018 </td><td colspan=1 rowspan=1 > DF </td><td colspan=1 rowspan=1 > Ghana </td><td class="highlighted"  colspan=1 rowspan=1 > Andy Yiadom </td><td class="highlighted"  colspan=1 rowspan=1 > Barnsley </td><td colspan=1 rowspan=1 > Free </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 5 June 2018 </td><td colspan=1 rowspan=1 > MF </td><td colspan=1 rowspan=1 > Republic of Ireland </td><td colspan=1 rowspan=1 > David Meyler </td><td colspan=1 rowspan=1 > Hull City </td><td colspan=1 rowspan=1 > Free </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 6 June 2018 </td><td colspan=1 rowspan=1 > DF </td><td colspan=1 rowspan=1 > Republic of Ireland </td><td colspan=1 rowspan=1 > John O'Shea </td><td colspan=1 rowspan=1 > Sunderland </td><td colspan=1 rowspan=1 > Free </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 6 July 2018 </td><td colspan=1 rowspan=1 > FW </td><td colspan=1 rowspan=1 > Scotland </td><td colspan=1 rowspan=1 > Marc McNulty </td><td colspan=1 rowspan=1 > Coventry City </td><td colspan=1 rowspan=1 > Undisclosed </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 17 July 2018 </td><td colspan=1 rowspan=1 > DF </td><td colspan=1 rowspan=1 > Netherlands </td><td colspan=1 rowspan=1 > Darren Sidoel </td><td colspan=1 rowspan=1 > Ajax </td><td colspan=1 rowspan=1 > Undisclosed </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 25 July 2018 </td><td colspan=1 rowspan=1 > GK </td><td colspan=1 rowspan=1 > England </td><td colspan=1 rowspan=1 > Sam Walker </td><td colspan=1 rowspan=1 > Colchester United </td><td colspan=1 rowspan=1 > Free </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 30 July 2018 </td><td colspan=1 rowspan=1 > FW </td><td colspan=1 rowspan=1 > England </td><td colspan=1 rowspan=1 > Sam Baldock </td><td colspan=1 rowspan=1 > Brighton & Hove Albion </td><td colspan=1 rowspan=1 > Undisclosed </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
What happened on On 17 May 2018?
Answer:
On 17 May 2018, Andy Yiadom from Ghana in position DF joined Reading from Barnsley free of fee.