Article: In January 2013, Destiny's Child released Love Songs, a compilation album of the romance-themed songs from their previous albums and a newly recorded track, "Nuclear". Beyoncé performed the American national anthem singing along with a pre-recorded track at President Obama's second inauguration in Washington, D.C. The following month, Beyoncé performed at the Super Bowl XLVII halftime show, held at the Mercedes-Benz Superdome in New Orleans. The performance stands as the second most tweeted about moment in history at 268,000 tweets per minute. At the 55th Annual Grammy Awards, Beyoncé won for Best Traditional R&B Performance for "Love on Top". Her feature-length documentary film, Life Is But a Dream, first aired on HBO on February 16, 2013. The film, which she directed and produced herself, featured footage from her childhood, her as a mother and businesswoman, recording, rehearsing for live performances, and her return to the spotlight following Blue Ivy's birth. Its DVD release in November 2013 was accompanied by footage from the Revel Presents: Beyoncé Live concerts and a new song, "God Made You Beautiful". In February 2013, Beyoncé signed a global publishing agreement with Warner/Chappell Music, which would cover her future songwriting and then-upcoming studio album.

Now answer this question: What did Beyonce sign in 2013?
global publishing agreement