Updated Zip Library documentation to mention compression features.

Signed-off-by: garrettair <garrettair@gmail.com>
diff --git a/user_guide_src/source/libraries/zip.rst b/user_guide_src/source/libraries/zip.rst
index 4ca1408..a6b98c2 100644
--- a/user_guide_src/source/libraries/zip.rst
+++ b/user_guide_src/source/libraries/zip.rst
@@ -88,6 +88,11 @@
 
 		The above example will place my_bio.txt inside a folder called personal.
 
+		You can change the level of compression and encoding that is used by the gzcompress function during compression::
+
+			$this->zip->compression_level = 0; // Disable compression
+			$this->zip->compression_encoding = ZLIB_ENCODING_GZIP;
+
 	.. method:: add_dir($directory)
 
 		:param	mixed	$directory: Directory name string or an array of multiple directories