Add link to Gatsby Crash Course (#5005)
Add link to Gatsby Crash Course (#5005)

Signed-off-by: Mike Allanson <4fe6e405006ae38dd82cea8575c6b1fe0de12001@gmail.com>
fk/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,0x80/gatsby,0x80/gatsby,fk/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,mingaldrichgan/gatsby,fk/gatsby