Add CREDITS file and script to generate. (Resolves ferritreader/ferrit#33)

scripts/gen-credits.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+# This scripts generates the CREDITS file in the repository root, which
+# contains a list of all contributors ot the Libreddit project.
+#
+# We use git-log to surface the names and emails of all authors and committers,
+# and grep will filter any automated commits due to GitHub.
+
+set -o pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")/../" || exit 1
+git --no-pager log --pretty='%an <%ae>%n%cn <%ce>' master \
+    | sort -t'<' -u -k1,1 -k2,2 \
+    | grep -Fv -- 'GitHub <noreply@github.com>' \
+    > CREDITS