add cursor-offset (pagination)

src/Endpoints/Endpoint.php

@@ -169,8 +169,8 @@ public function limit(int $limit): Endpoint
      */
     public function offset(StartCursor $startCursor): Endpoint
     {
-        // toDo
-        throw HandlingException::instance('Not implemented yet.', compact($startCursor));
+        $this->startCursor = $startCursor;
+        return $this;
     }
 
 }

src/Query/Filters/Operators.php

@@ -9,7 +9,7 @@ class Operators
     # ToDo: Make this a enum with PHP 8.1
     const EQUALS = 'equals';
     const DOES_NOT_EQUAL = 'does_not_equal';
-    const CONTAINS = 'contain';
+    const CONTAINS = 'contains';
     const DOES_NOT_CONTAIN = 'does_not_contain';
     const STARTS_WITH = 'starts_with';
     const ENDS_WITH = 'ends_with';

src/Query/StartCursor.php

@@ -21,4 +21,8 @@ public function __construct(string $cursor)
     {
         $this->cursor = $cursor;
     }
+
+    public function __toString() {
+        return $this->cursor;
+    }
 }