Documents basic use.

Author: ryasmi

docs/readme.md

@@ -0,0 +1,30 @@
+# Getting Started
+
+Basic use.
+```php
+use \Locker\XApi\Statement as Statement;
+
+// Returns the given statement as a string of JSON.
+function getJsonStatement($statement) {
+  return $statement->toJson();
+}
+
+// Returns the given errors as a string of JSON.
+function getJsonValidationErrors($errors) {
+  return json_encode(array_map(function ($error) {
+    $error->addTrace('statement');
+    return (string) $error;
+  }, $errors));
+}
+
+// Creates a statement and validates it.
+$statement = Statement::createFromJson($json_string);
+$errors = $statement->validate();
+
+// Outputs validation errors or the statement as JSON.
+if (empty($errors)) {
+  echo getJsonStatement($statement);
+} else {
+  echo getJsonValidationErrors($errors);
+}
+```