Add Homebrew "dive" formula

Add the formula for dive (1), a tool for exploring a docker image, layer
contents, and discovering ways to shrink your Docker image size.

The formula is available through the `wagoodman/dive` tap.

References:
  (1) https://github.com/wagoodman/dive

Resolves GH-177

snowflakes/homebrew/Brewfile

@@ -16,6 +16,7 @@ tap "homebrew/cask-fonts"
 tap "homebrew/cask-versions"
 tap "homebrew/core"
 tap "homebrew/livecheck"
+tap "wagoodman/dive"
 
 brew "asciinema"
 brew "awscli"
@@ -32,6 +33,7 @@ brew "ctop"
 brew "dep"
 brew "diffutils"
 brew "diff-so-fancy"
+brew "dive"
 brew "docker-completion"
 brew "docker-compose-completion"
 brew "e2fsprogs"