guides/Docker.md in pghero-2.0.0 vs guides/Docker.md in pghero-2.0.1

@@ -36,8 +36,30 @@
 docker run -ti -e DATABASE_URL=... ankane/pghero bin/rake pghero:capture_query_stats
 ```
 
 After this, a time range slider will appear on the Queries tab.
 
+## Historical Space Stats
+
+To track space stats over time, create a table to store them.
+
+```sql
+CREATE TABLE "pghero_space_stats" (
+  "id" serial primary key,
+  "database" text,
+  "schema" text,
+  "relation" text,
+  "size" bigint,
+  "captured_at" timestamp
+)
+CREATE INDEX ON "pghero_space_stats" ("database", "captured_at")
+```
+
+Schedule the task below to run once a day.
+
+```sh
+docker run -ti -e DATABASE_URL=... ankane/pghero bin/rake pghero:capture_space_stats
+```
+
 ## Credits
 
 Thanks to [Brian Morton](https://github.com/bmorton) for the [original Docker image](https://github.com/bmorton/pghero_solo).