Merge pull request #43 from lionheart-pacific/tools-rectangle

Add Rectangle window manager

Author: infews

tools.md

@@ -31,3 +31,6 @@ There are dozens of these in the wild, but with the advent of Apple Silicon, man
       - `brew install --cask fertigt-slate`
     - [Intel Slate](https://github.com/mattr-/slate) - deprecated b/c of Apple Silicon
       - `brew install --cask mattr-slate`
+- [Rectangle](https://github.com/rxhanson/Rectangle)
+  - Similar to ShiftIt. Actively maintained.
+  - `brew install --cask rectangle`