Document schema overrides

README.md

@@ -301,6 +301,21 @@ If a column has multiple jsonschema types, the following order is using to order
 - BOOLEAN
 - NOTYPE
 
+### Using the Singer catalog to narrow down the Postgres data types
+
+You can use [Singer catalog's schema](https://github.com/singer-io/getting-started/blob/master/docs/DISCOVERY_MODE.md#schemas) to override the data types coming from the tap. The easiest way to do this is to use Meltano and its [schema setting](https://docs.meltano.com/concepts/plugins/#schema-extra) for the tap:
+
+```yaml
+# meltano.yml
+plugins:
+  extractors:
+  - name: tap-my-tap
+    schema:
+      my_column:
+        type: integer
+        maximum: 1000  # This will be mapped to 'smallint'
+```
+
 ## Content Encoding Support
 
 Json Schema supports the [`contentEncoding` keyword](https://datatracker.ietf.org/doc/html/rfc4648#section-8), which can be used to specify the encoding of input string types.