Add homebrew on Linux and macOS
This adds directions that will work when
is merged.  If that is
not merged, we can create a tap and adjust these directions accordingly.
@@ -187,8 +187,28 @@ nix profile install 'github:martinvonz/jj'
```
+#### Homebrew
+
+If you use linuxbrew, you can run:
+
+```shell script
+brew install jj
+```
+
+
### Mac
+#### Homebrew
+
+If you use Homebrew, you can run:
+
+```shell script
+brew install jj
+```
+
+
+#### From Source
+
You may need to run some or all of these:
```shell script
xcode-select --install
