graphite-project/graphite-web — pull request #949 by esc (2014-09-08 14:02:42+00:00)
Title: use add instead of set for rendered cache

As per b9b635043acf2f5dd5be712f5e06b9911d16842f prefer 'add' over 'set'. This
is a fix for the cached renderings (images) which wasn't addressed in the
original bug fix.

Fix for 0.9.x

cc @obfuscurity