Fix support for --grant=false argument (#59)

Author: danielbachhuber

features/cap.feature

@@ -20,7 +20,7 @@ Feature: Manage Cap
       Success: Added 1 capability to 'contributor' role.
       """
 
-    When I run `wp cap add contributor behold observe`
+    When I run `wp cap add contributor behold observe --grant`
     Then STDOUT should contain:
       """
       Success: Added 2 capabilities to 'contributor' role.
@@ -38,6 +38,12 @@ Feature: Manage Cap
       Success: Added 2 capabilities to 'contributor' role as false.
       """
 
+    When I run `wp cap add contributor inspire --grant=false`
+    Then STDOUT should contain:
+      """
+      Success: Added 1 capability to 'contributor' role as false.
+      """
+
     When I run `wp cap list contributor`
     Then STDOUT should contain:
       """

src/Capabilities_Command.php

@@ -138,7 +138,10 @@ public function add( $args, $assoc_args ) {
 
 		$role_obj = self::get_role( $role );
 
-		$grant = ! isset( $assoc_args['grant'] ) || ! empty( $assoc_args['grant'] );
+		$grant = true;
+		if ( isset( $assoc_args['grant'] ) ) {
+			$grant = ! $assoc_args['grant'] || 'false' === $assoc_args['grant'] ? false : true;
+		}
 
 		$count = 0;