raw representable support for postgres data (vapor#105)

Author: tanner0101

Sources/PostgresNIO/Data/PostgresData+RawRepresentable.swift

@@ -0,0 +1,16 @@
+extension RawRepresentable where Self.RawValue: PostgresDataConvertible {
+    static var postgresDataType: PostgresDataType {
+        RawValue.postgresDataType
+    }
+
+    init?(postgresData: PostgresData) {
+        guard let rawValue = RawValue.init(postgresData: postgresData) else {
+            return nil
+        }
+        self.init(rawValue: rawValue)
+    }
+
+    var postgresData: PostgresData? {
+        self.rawValue.postgresData
+    }
+}