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:
Allie X
Table title:
Songwriting credits
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Year </th><th colspan=1 rowspan=1 > Artist </th><th colspan=1 rowspan=1 > Title </th><th colspan=1 rowspan=1 > Album </th></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=7 > 2015 </td><td class="highlighted"  colspan=1 rowspan=7 > Troye Sivan </td><td colspan=1 rowspan=1 > "Bite" </td><td colspan=1 rowspan=1 > Wild EP </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > "Talk Me Down" </td><td class="highlighted"  colspan=1 rowspan=6 > Blue Neighbourhood </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > "Youth" </td></tr>
<tr> <td colspan=1 rowspan=1 > "Lost Boy" </td></tr>
<tr> <td colspan=1 rowspan=1 > "For Him." </td></tr>
<tr> <td colspan=1 rowspan=1 > "Suburbia" </td></tr>
<tr> <td colspan=1 rowspan=1 > "Swimming Pools" </td></tr>
<tr> <td colspan=1 rowspan=4 > 2017 </td><td colspan=1 rowspan=1 > Seohyun </td><td colspan=1 rowspan=1 > "Moonlight" </td><td colspan=1 rowspan=1 > Don't Say No </td></tr>
<tr> <td colspan=1 rowspan=1 > Lea Michele </td><td colspan=1 rowspan=1 > "Heavy Love" </td><td colspan=1 rowspan=1 > Places </td></tr>
<tr> <td colspan=1 rowspan=1 > Jaira Burns </td><td colspan=1 rowspan=1 > "Ugly" </td><td colspan=1 rowspan=1 > Non-album single </td></tr>
<tr> <td colspan=1 rowspan=1 > B.A.P </td><td colspan=1 rowspan=1 > "Think Hole" </td><td colspan=1 rowspan=1 > Ego </td></tr>
<tr> <td colspan=1 rowspan=5 > 2018 </td><td colspan=1 rowspan=5 > Troye Sivan </td><td colspan=1 rowspan=1 > "Seventeen" </td><td colspan=1 rowspan=5 > Bloom </td></tr>
<tr> <td colspan=1 rowspan=1 > "The Good Side" </td></tr>
<tr> <td colspan=1 rowspan=1 > "Plum" </td></tr>
<tr> <td colspan=1 rowspan=1 > "What a Heavenly Way to Die" </td></tr>
<tr> <td colspan=1 rowspan=1 > "Animal" </td></tr>
</table>
Question:
How did Allie X contribute to Troye Sivan's album Blue Neighbourhood in 2015?
Answer:
In 2015, Allie X contributed to Troye Sivan's album Blue Neighbourhood by writing for albums singles "Talk Me Down" and "Youth".