From 9129d6d1713761487dfd2400d1e87be10e4b900f Mon Sep 17 00:00:00 2001
From: Valentin Brandl <vbrandl@riseup.net>
Date: Fri, 19 Apr 2019 22:57:32 +0200
Subject: [PATCH] Document the caching mechanism

---
 doc/caching.md | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 doc/caching.md

diff --git a/doc/caching.md b/doc/caching.md
new file mode 100644
index 0000000..4808e49
--- /dev/null
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+# Caching
+
+To prevent calculating the whole stats each time, the `HEAD` and HoC is cached, once it was calculated. If a cached
+version is found, current `HEAD` and cached `HEAD` are compared, if they are the same, the cached value is returned,
+else only the HoC between the cached `HEAD` and the current `HEAD` is calculated, added to the cached score and the
+cache gets updated.