Added .gitignore template from slimer repo
Added .gitignore template from slimer repo

refs #9441

https://github.com/TryGhost/slimer/blob/1ae82d4325ad5e2541e85c3465934127c00eb34b/packages/generator-slimer/generators/gitroot/templates/gitignore.tpl

bitjson/Ghost,e10/Ghost,Gargol/Ghost,TryGhost/Ghost,JohnONolan/Ghost,Kikobeats/Ghost,TryGhost/Ghost,ErisDS/Ghost,Kikobeats/Ghost,e10/Ghost,janvt/Ghost,ErisDS/Ghost,Gargol/Ghost,ErisDS/Ghost,Kikobeats/Ghost,TryGhost/Ghost,JohnONolan/Ghost,janvt/Ghost,kevinansfield/Ghost,kevinansfield/Ghost,JohnONolan/Ghost,bitjson/Ghost,kevinansfield/Ghost