Sunderland are one of the oldest and most popular clubs in English football. They currently boast six English first division titles in their trophy cabinet, along with two FA Cups, one FA Community Shield and one EFL Trophy.However, they've struggled in recent years. After a torrid 2016-17 season, the Black Cats were relegated to the Championship for the first time in 10 years. Their ignominy didn't end there, however, as another poor season in the 2017-18 EFL campaign saw them drop down to League One.Since then, Sunderland have finished fifth, seventh and fourth, narrowly missing out on promotion to the Championship last season. A 3-2 loss on aggregate against Lincoln City FC in the League One playoff semifinals put paid to their chances.It's another season in League One for Sunderland after their play-off loss to Lincoln City.Reaction: ⚽️📲 https://t.co/5Du5Yilmm1#bbcfootball #bbcefl #SUNLIN pic.twitter.com/9NwRgWK6VL— BBC 5 Live Sport (@5liveSport) May 22, 2021Sunderland will once again push for promotion this season but need to make improvements to their squad before they can mount a serious challenge.On that note, here's a list of three signings who could help Sunderland win promotion to the EFL Championship this season:#3 Ibou Touray (Salford City) | Left backIbou Touray impressed with his performances for Salford City in League One last seasonSunderland were forced to play youngster Daniel Neil at left back in this season's opener against Wigan Athletic in the absence of the injured Denver Hume.Signing a new left back has been among the key priorities for the Black Cats this transfer season. To that end, they've been linked to Salford City's Ibou Touray of late.The League Two Player of the Year Award at the @NWFAwards has been awarded to Ibou Touray of Salford City, who came through the academy at #EFC #NWFA2020 pic.twitter.com/BaYIJlODCV— BBC Sport Merseyside (@bbcmerseysport) November 9, 2020Touray joined Salford City from Nantwich Town in 2017 and played a key role in their promotion from the National League North to EFL League Two. The 26-year-old played 142 games in all competitions for the Cheshire-based club thus far, scoring nine goals.The Liverpool-born defender also won the NWFA League Two Player of the Year 2020 accolade.