clustering guide

[lukemarsden]

probably under concepts, maybe also some material under tasks

• how dotmesh clustering works
• what it does (replicate all commits to all nodes in the cluster, supports moving branches from one node to another _assuming both the source and destination node are up)
• the limitations (https://twitter.com/getdotmesh/status/961878130834247681)
  • also: there's currently no way to "recover from a commit" -- if a node goes down and doesn't come back, that branch will be unrecoverable without manual intervention at the etcd level

there's a plan to write a blog post about this too, but it would deserves dedicated permanent section in the docs too!

[lukemarsden]

smash helps with bullet 3 subbullet 1!