Last minute fix for people who already installed the ext

Maybe they run into errors because I had to rename the migration class
I added the effectively_installed() function then to second migration
because it made me feel more safe.

migrations/release_1_0_0_rc1.php

@@ -11,6 +11,13 @@
 
 class release_1_0_0_rc1 extends \phpbb\db\migration\migration
 {
+	public function effectively_installed()
+	{
+		// This should be implemented because I had to rename the class (from uppercase to lowercase)
+		// And checking for config should be enough because schema won't exist if config doesn't exist.
+		return isset($this->config['ppp_maximum_ppp']);
+	}
+
 	public function update_schema()
 	{
 		return array(

migrations/release_1_0_0_rc2.php

@@ -16,6 +16,11 @@ static public function depends_on()
 		return array('\elsensee\postsperpage\migrations\release_1_0_0_rc1');
 	}
 
+	public function effectively_installed()
+	{
+		return isset($this->config['ppp_maximum_topic_ppp']);
+	}
+
 	public function update_schema()
 	{
 		return array(