diff --git a/docs/AddCollaboratorOption.md b/docs/AddCollaboratorOption.md
index d6dcfe9..37813fe 100644
--- a/docs/AddCollaboratorOption.md
+++ b/docs/AddCollaboratorOption.md
@@ -3,4 +3,12 @@
 ## Properties
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-**permission** | **String** |  |  [optional]
+**permission** | [**PermissionEnum**](#PermissionEnum) |  |  [optional]
+
+<a name="PermissionEnum"></a>
+## Enum: PermissionEnum
+Name | Value
+---- | -----
+READ | &quot;read&quot;
+WRITE | &quot;write&quot;
+ADMIN | &quot;admin&quot;
diff --git a/src/main/java/org/gitnex/tea4j/v2/models/AddCollaboratorOption.java b/src/main/java/org/gitnex/tea4j/v2/models/AddCollaboratorOption.java
index 1c886d9..f28dcc8 100644
--- a/src/main/java/org/gitnex/tea4j/v2/models/AddCollaboratorOption.java
+++ b/src/main/java/org/gitnex/tea4j/v2/models/AddCollaboratorOption.java
@@ -12,8 +12,13 @@
 
 package org.gitnex.tea4j.v2.models;
 
+import com.google.gson.TypeAdapter;
+import com.google.gson.annotations.JsonAdapter;
 import com.google.gson.annotations.SerializedName;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
 import io.swagger.v3.oas.annotations.media.Schema;
+import java.io.IOException;
 import java.io.Serializable;
 import java.util.Objects;
 
@@ -23,11 +28,56 @@ import java.util.Objects;
         "AddCollaboratorOption options when adding a user as a collaborator of a repository")
 public class AddCollaboratorOption implements Serializable {
   private static final long serialVersionUID = 1L;
+  /** Gets or Sets permission */
+  @JsonAdapter(PermissionEnum.Adapter.class)
+  public enum PermissionEnum {
+    READ("read"),
+    WRITE("write"),
+    ADMIN("admin");
+
+    private String value;
+
+    PermissionEnum(String value) {
+      this.value = value;
+    }
+
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    public static PermissionEnum fromValue(String input) {
+      for (PermissionEnum b : PermissionEnum.values()) {
+        if (b.value.equals(input)) {
+          return b;
+        }
+      }
+      return null;
+    }
+
+    public static class Adapter extends TypeAdapter<PermissionEnum> {
+      @Override
+      public void write(final JsonWriter jsonWriter, final PermissionEnum enumeration)
+          throws IOException {
+        jsonWriter.value(String.valueOf(enumeration.getValue()));
+      }
+
+      @Override
+      public PermissionEnum read(final JsonReader jsonReader) throws IOException {
+        Object value = jsonReader.nextString();
+        return PermissionEnum.fromValue((String) (value));
+      }
+    }
+  }
 
   @SerializedName("permission")
-  private String permission = null;
+  private PermissionEnum permission = null;
 
-  public AddCollaboratorOption permission(String permission) {
+  public AddCollaboratorOption permission(PermissionEnum permission) {
     this.permission = permission;
     return this;
   }
@@ -38,11 +88,11 @@ public class AddCollaboratorOption implements Serializable {
    * @return permission
    */
   @Schema(description = "")
-  public String getPermission() {
+  public PermissionEnum getPermission() {
     return permission;
   }
 
-  public void setPermission(String permission) {
+  public void setPermission(PermissionEnum permission) {
     this.permission = permission;
   }