add cfwheels gitignore

CFWheels.gitignore

@@ -0,0 +1,12 @@
+# unpacked plugin folders
+plugins/**/*
+
+# files directory where uploads go
+files
+
+# DBMigrate plugin: generated SQL
+db/sql
+
+# AssetBundler plugin: generated bundles
+javascripts/bundles
+stylesheets/bundles