examples: Extend example with basic trust schema (validator-config)

Change-Id: Iaf9f4abd57563e52cb167b55ba3b27d8ecc1ecd7
diff --git a/examples/trust-schema.conf b/examples/trust-schema.conf
new file mode 100644
index 0000000..aade06c
--- /dev/null
+++ b/examples/trust-schema.conf
@@ -0,0 +1,34 @@
+rule
+{
+  id "Example rule"
+  for data
+  filter
+  {
+    type name
+    name /example/testApp
+    relation is-prefix-of
+  }
+  checker
+  {
+    type customized
+    sig-type ecdsa-sha256
+    key-locator
+    {
+      type name
+      hyper-relation
+      {
+        k-regex ^(<>*)<KEY><><>?<>?$
+        k-expand \\1
+        h-relation is-prefix-of
+        p-regex ^(<>*)<>*$
+        p-expand \\1
+      }
+    }
+  }
+}
+
+trust-anchor
+{
+  type file
+  file-name "example-trust-anchor.cert"
+}