add signal config dir for macos

README.md

@@ -35,12 +35,21 @@ First build the docker container for the tool
     Successfully tagged sigint:latest
 
 The following command will run the analysis against the signal config directory
-you point it to, and dump the output to ./output/table.csv:
+you point it to, and dump the output to ./output/table.csv
+
+## Linux
 
     $ ./run.sh -c ~/.config/Signal
 
     INFO:main:writing message count table to /output/table.csv
 
+## Macos
+
+    $ ./run.sh -c ~/Library/Application\ Support/Signal
+
+    INFO:main:writing message count table to /output/table.csv
+
+## Group Filtering
 
 Adding -f will filter the groups under consideration to only those listed in
 config/chat_list.txt