Added recommended gitignore rules from Craft

Signed-off-by: Ryan Shrum <ryan@ehousestudio.com>

CraftCMS.gitignore

+.DS_Store
+
+# Craft Storage (cache) [http://buildwithcraft.com/help/craft-storage-gitignore]
+/craft/storage/*
+!/craft/storage/logo/*
\ No newline at end of file