Update README

Author: kyleconroy

README.md

@@ -1 +1,19 @@
-Fork of https://github.com/jackc/pgtype
+[![Go Reference](https://pkg.go.dev/badge/github.com/tabbed/pqtype.svg)](https://pkg.go.dev/github.com/tabbed/pqtype)
+![CI](https://github.com/tabbed/pqtype/workflows/ci/badge.svg)
+
+# pqtype
+
+pqtype implements Go types for PostgreSQL types when using the
+[lib/pq](https://github.com/lib/pq) driver. 
+
+## Compatibility
+
+pqtype is tested against PostgreSQL 9.6 through 13 and Go 1.13 through 1.17.
+While these types may work with other drivers, they are **only** tested against
+the lib/pq driver.
+
+## History
+
+pqtype is a fork of [jackc/pgtype](https://github.com/jackc/pgtype) with all
+the pgx-specific code removed. The `Status` field on types has been replaced
+with a `Valid` boolean to mirror the standard library `sql.Null*` types.