Add cannot ignore staff error

errors.js

@@ -195,6 +195,12 @@ const ErrAssetURLAlreadyExists = new APIError('Asset URL already exists, cannot
   status: 409
 });
 
+// ErrCannotIgnoreStaff is returned when a user tries to ignore a staff member.
+const ErrCannotIgnoreStaff = new APIError('Cannot ignore staff members.', {
+  translation_key: 'CANNOT_IGNORE_STAFF',
+  status: 400
+});
+
 module.exports = {
   ExtendableError,
   APIError,
@@ -221,5 +227,6 @@ module.exports = {
   ErrLoginAttemptMaximumExceeded,
   ErrEditWindowHasEnded,
   ErrCommentTooShort,
-  ErrAssetURLAlreadyExists
+  ErrAssetURLAlreadyExists,
+  ErrCannotIgnoreStaff
 };

locales/en.yml

@@ -206,6 +206,7 @@ en:
     NOT_FOUND: "Resource not found"
     ALREADY_EXISTS: "Resource already exists"
     INVALID_ASSET_URL: "Assert URL is invalid"
+    CANNOT_IGNORE_STAFF: "Cannot ignore Staff members."
     email: "Not a valid E-Mail"
     confirm_password: "Passwords don't match. Please check again"
     network_error: "Failed to connect to server. Check your internet connection and try again."