Invite users to join Slack instead of Gitter (#1385)
Invite users to join Slack instead of Gitter (#1385)

Since the team is now on Slack.
Vivalldi/grav,joeyhenricks/a-broke-vegan,Vivalldi/grav,tomzx/blog.tomrochette.com,getgrav/grav,webuxr/iamrs,joeyhenricks/a-broke-vegan,stell/grav,dimayakovlev/grav,ccardinaux/grav-test,tomzx/blog.tomrochette.com,tomzx/blog.tomrochette.com,shortsofia/testesitegrav.github.io,notklaatu/grav,tomzx/blog.tomrochette.com,Sommerregen/grav,getgrav/grav,notklaatu/grav,dimayakovlev/grav