Looking to Gain Weight for the Wedding Day

Been using FB videos on and off for the past year but finally signed up. The goal is to gain 15-20 lbs before our wedding in April next year. I've always been told I'm too thin. Both my sister and mom made a few too many comments about my weight at my first wedding dress shopping day, so, I guess it's time to take this on. I'm a regular yogi and eat meat/dairy 2-3 times per week, making most of my meals vegetarian/vegan. Any tips for this over-ambitious goal?