Add info about new classifiers table to readme

Author: edgarrmondragon

README.md

@@ -26,6 +26,7 @@ ackg|0.0.5||0|0|2021-01-21 04:37:10
 - Direct requirements (`requires_dist`)
 - Extra requirements (`requires_extras`)
 - Python requirements (`requires_python`)
+- Trove classifiers (`classifiers`)
 - Yanked versions (`yanked`)
 - Wheel data (`build_tag`, `python_tags`, `abi_tags`, `platform_tags`)
 - Maintainers on PyPI
@@ -94,6 +95,14 @@ CREATE TABLE scorecard_checks (
     name STRING,
     score INTEGER
 )
+
+-- Trove Classifiers --
+CREATE TABLE classifiers (
+    package_name TEXT,
+    name TEXT,
+    PRIMARY KEY (package_name, name),
+    FOREIGN KEY (package_name) REFERENCES packages(name)
+)
 ```
 
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