The game of Baseball was in existence well before the Civil War, and it's roots actually extend outside of America. The modern game of baseball as we know it is based on the "Knickerbocker Rules" which were put into place by Alexander Cartwright, who is generally credited as being the creator of baseball. However, there's no record of him having served as a General in the Union Army, or even having been involved in the Civil War, for that matter - he was in Hawaii, serving as the Fire Chief of the Honolulu Fire Department during that time.
You're probably thinking of Abner Doubleday, who was credited for it in the early 20th century - however, that notion was later dismissed, and Congress formally recognised Cartwright as the game's creator sometime in the 1950s.
Doubleday
It is a myth perpetuated by Spaulding that Abner Doubleday created Baseball. He was nowhere near Cooperstown on the day the myth gives for its creation story. See Ken Burns' Baseball.
Gettysburg
The Battle of Gettysburg was fought in Gettysburg, Pennsylvania.
He fought on the union side.
George Gordon Meade fought in The Battle of Gettysburg.
The Battle of Gettysburg was fought July 1, 2, and 3 in the year 1863
Gettysburg was fought in 1863.
The Battle of Gettysburg was fought in and around Gettysburg, Pennsylvania.
Yes. Gettysburg is in Pennsylvania.
Union and confederate soldiers fought at Gettysburg.
The South fought the North.