fix dangling sentence in mutagen readme and permissions

Change-Id: I653e04c481930c44f869e4313fa122e13db5163f
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/257043
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: James Butters <jbutters@instructure.com>
QA-Review: Keith Garner <kgarner@instructure.com>
Product-Review: Keith Garner <kgarner@instructure.com>

docker-compose/mutagen/README.md

@@ -57,7 +57,8 @@ mutagen forums, this will go away.)
 
 **Q: Help! My file changes aren't reflecting in the docker container if I use `mutagen compose run ...`**
 
-**A:** Be sure to run `mutagen compose up --no-start web` first or files won't sync. (Run doesn't activate the
+**A:** Be sure to run `mutagen compose up --no-start web` first or files won't sync. (Run doesn't activate the mutagen
+daemon or container.)
 
 **Q: Something seems to be wrong with the sync process, how do I get more information?**
 

docker-compose/mutagen/docker-compose.override.yml

@@ -57,8 +57,8 @@ x-mutagen:
       beta: "volume://code"
       configurationBeta:
         permissions:
-          defaultOwner: "docker"
-          defaultGroup: "docker"
+          defaultOwner: "id:9999"
+          defaultGroup: "id:9999"
       ignore:
         paths:
           - "/.bundle/"
@@ -79,8 +79,6 @@ x-mutagen:
           - "!/app/stylesheets/brandable_css_brands/"
           - "/app/stylesheets/brandable_css_brands/*"
           - "/packages/canvas-rce/canvas"
-          - "!/public/javascripts/client_apps/"
-          - "/public/javascripts/client_apps/*"
           - "!/public/dist/"
           - "/public/dist/*"
           - "!/public/javascripts/compiled/"