🖊️ document env vars

.env.example-full

@@ -27,6 +27,12 @@ IMAGE_HOSTING_R2_CDN_URL=
 IMAGE_HOSTING_R2_BUCKET_PATH=
 R2_ACCESS_KEY_ID=  # optional
 R2_SECRET_ACCESS_KEY=  # optional
+# These two GRAPHER_CONFIG_ settings are used to store grapher configs in an R2 bucket.
+# The cloudflare workers for thumbnail rendering etc use these settings to fetch the grapher configs.
+# This means that for most local dev it is not necessary to set these.
+GRAPHER_CONFIG_R2_BUCKET= # optional - for local dev set it to "owid-grapher-configs-staging"
+GRAPHER_CONFIG_R2_BUCKET_PATH= # optional - for local dev set it to "devs/YOURNAME"
+
 
 OPENAI_API_KEY=