RAELYNN shared some big news yesterday on Instagram . . . but it had nothing to do with her career.  She wrote that her husband Josh Davis had joined the military . . . and he left for basic training on Monday. She loves him for it, though, and totally backs his decision.  Here’s some of what she wrote:  “My husband has always supported me in everything that I’ve wanted to do . . . and yesterday began a new adventure for us. “Joshua left for basic training to serve in our military and serve his country.  Saying I’m proud doesn’t scratch the surface of how I feel.  I love his heart and the man that he is more and more every single day.” She hopes you’ll keep him in your prayers . . . and she, in turn, sends prayers to all of the families who have loved ones that are serving. No worries about her being alone.  She’s one of the openers on BLAKE SHELTON’s “Doing It To Country Songs” tour, which kicks off tomorrow.  Also, I still remember their wedding, which was about a year ago . . . because she had 17 bridesmaids.