Just exposing permission type enum until there's more to this relation than one property

src/main/java/org/kohsuke/github/GHPermission.java

@@ -24,11 +24,13 @@
 
 package org.kohsuke.github;
 
+import java.util.Locale;
+
 /**
  * Permission for a user in a repository.
  * @see <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API</a>
  */
-public class GHPermission {
+/*package*/ class GHPermission {
 
     private String permission;
     private GHUser user;
@@ -40,6 +42,10 @@ public class GHPermission {
         return permission;
     }
 
+    public GHPermissionType getPermissionType() {
+        return Enum.valueOf(GHPermissionType.class, permission.toUpperCase(Locale.ENGLISH));
+    }
+
     public GHUser getUser() {
         return user;
     }

src/main/java/org/kohsuke/github/GHPermissionType.java

@@ -0,0 +1,11 @@
+package org.kohsuke.github;
+
+/**
+ * @author Kohsuke Kawaguchi
+ */
+public enum GHPermissionType {
+    ADMIN,
+    WRITE,
+    READ,
+    NONE
+}

src/main/java/org/kohsuke/github/GHRepository.java

@@ -486,10 +486,19 @@ public class GHRepository extends GHObject {
      * @throws FileNotFoundException under some conditions (e.g., private repo you can see but are not an admin of); treat as unknown
      * @throws HttpException with a 403 under other conditions (e.g., public repo you have no special rights to); treat as unknown
      */
-    public GHPermission getPermission(String user) throws IOException {
+    public GHPermissionType getPermission(String user) throws IOException {
         GHPermission perm = root.retrieve().withHeader("Accept", "application/vnd.github.korra-preview").to(getApiTailUrl("collaborators/" + user + "/permission"), GHPermission.class);
         perm.wrapUp(root);
-        return perm;
+        return perm.getPermissionType();
+    }
+
+    /**
+     * Obtain permission for a given user in this repository.
+     * @throws FileNotFoundException under some conditions (e.g., private repo you can see but are not an admin of); treat as unknown
+     * @throws HttpException with a 403 under other conditions (e.g., public repo you have no special rights to); treat as unknown
+     */
+    public GHPermissionType getPermission(GHUser u) throws IOException {
+        return getPermission(u.getLogin());
     }
 
     /**