Update CakePHP.gitignore

Ignore all tmp and log files but preserve the directory structure

CakePHP.gitignore

@@ -2,8 +2,20 @@
 
 /vendor/*
 /config/app.php
-/tmp/*
+
+/tmp/cache/models/*
+!/tmp/cache/models/empty
+/tmp/cache/persistent/*
+!/tmp/cache/persistent/empty
+/tmp/cache/views/*
+!/tmp/cache/views/empty
+/tmp/sessions/*
+!/tmp/sessions/empty
+/tmp/tests/*
+!/tmp/tests/empty
+
 /logs/*
+!/logs/empty
 
 # CakePHP 2