Add info on etc/db files

etc/db/README.md

@@ -0,0 +1,21 @@
+# Database configuration
+
+## Database template (`database-template.sql`)
+
+Used on installation to create the Dougal database.
+
+Created with:
+
+```bash
+pg_dump -U postgres --create --schema-only --exclude-schema='survey_*' dougal >database-template.sql
+```
+
+## Schema template (`schema-template.sql`)
+
+Used by [`bin/create-survey.sh`](../../bin/create-survey.sh) during project creation to add and populate a new schema.
+
+Created with:
+
+```bash
+SCHEMA_NAME=survey_X EPSG_CODE=XXXXX $DOUGAL_ROOT/sbin/dump_schema.sh
+```