Create 2018-04-04-mentoring-groups-open.md
Create 2018-04-04-mentoring-groups-open.md

adding Kari's post

Former-commit-id: 34ecb285e8cea7b4188b20857ec7f3015166bf19 [formerly 5cfaba72610e71f6ac02a977632f2056d1e7431d]
Former-commit-id: dee9402a7bc414f4cefb92baab32d72fef22c102
LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io