Disable caching

README.md

@@ -18,12 +18,15 @@ Next enable anyone on the internet to be able to read the badges (necessary if y
 gsutil defacl ch -u AllUsers:R gs://${GOOGLE_CLOUD_PROJECT}-badges/
 ```
 
-Then upload the pre-generated badges in `./badges` to the bucket (ensure they go into a directory on the bucket named `badges/`):
+Then upload the pre-generated badges in `./badges` to the bucket. Ensure they go into a directory on the bucket named `badges/`. Disable caching to ensure the latest updates to a badge are visible to end-users.
 
 ```bash
-gsutil -m cp ./badges/*.svg gs://${GOOGLE_CLOUD_PROJECT}-badges/badges/
+gsutil -m -h "Cache-Control:no-cache,max-age=0" \
+  cp ./badges/*.svg gs://${GOOGLE_CLOUD_PROJECT}-badges/badges/
 ```
 
+Note: the `-m` flag uploads the badges in parallel, speeding it up.
+
 ### Configure IAM
 
 Create a new service account for use by the Cloud Function:
@@ -64,4 +67,4 @@ Ensure the following environment variables are set first:
 
 * `BADGES_BUCKET`: the name of the bucket containing the badges
 
-You'll also need to install [jq](https://stedolan.github.io/jq/) and [xq](https://github.com/jeffbr13/xq).
+You'll also need to install [jq](https://stedolan.github.io/jq/) and [xq](https://github.com/jeffbr13/xq).