Fix brew osxfuse install instructions.

Reported by @ejholmes at:

* #177 (comment)

License: MIT
Signed-off-by: Steven Allen <steven@stebalien.com>

docs/fuse.md

@@ -18,7 +18,12 @@ Depending on whether you are using OSX or Linux, follow the proceeding instructi
 
 ## Mac OSX -- OSXFUSE
 
-It has been discovered that versions of `osxfuse` prior to `2.7.0` will cause a kernel panic. For everyone's sake, please upgrade (latest at time of writing is `2.7.4`). The installer can be found at https://osxfuse.github.io/. There is also a homebrew formula (`brew install osxfuse`) but users report best results installing from the official OSXFUSE installer package.
+It has been discovered that versions of `osxfuse` prior to `2.7.0` will cause a kernel panic. For everyone's sake, please upgrade (latest at time of writing is `2.7.4`). The installer can be found at https://osxfuse.github.io/. There is also a homebrew formula using cask but users report best results installing from the official OSXFUSE installer package:
+
+```sh
+brew tap caskroom/cask # if you don't have cask yet
+brew cask install osxfuse
+```
 
 Note that `ipfs` attempts an automatic version check on `osxfuse` to prevent you from shooting yourself in the foot if you have pre `2.7.0`. Since checking the OSXFUSE version [is more complicated than it should be], running `ipfs mount` may require you to install another binary: