Add refData controller.

src/main/java/org/cerberus/controllers/RefDataController.java

@@ -0,0 +1,18 @@
+package org.cerberus.controllers;
+
+import org.cerberus.core.constant.Role;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.Arrays;
+import java.util.List;
+
+@RestController
+@RequestMapping("/api/refData")
+public class RefDataController {
+    @GetMapping("/roles")
+    public List<Role> getRoles() {
+        return Arrays.asList(Role.values());
+    }
+}