Added readme

t.ts

@@ -0,0 +1,11 @@
+import {
+  ValidationError, validate,
+  isBoolean
+} from "./mod.ts";
+
+const converted: any = {};
+const errors: ValidationError[] = await validate("foobar", isBoolean(), { doConversion: true, converted });
+console.log(errors);
+// [ { type: "isBoolean", args: {}, message: "This value has to be a boolean." } ]
+console.log(converted);
+// { output: "foobar" }