Add gather_coverage.sh script.

cover/gather_coverage.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+# This scripts copies all the coverage reports from various circle shards,
+# merges them and produces a complete report.
+
+set -ex
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+DESTINATION=$1
+FROMDIR=$2
+mkdir -p $DESTINATION
+
+if [ -n "$CIRCLECI" ]; then
+    for i in $(seq 1 $(($CIRCLE_NODE_TOTAL - 1))); do
+        scp node$i:$FROMDIR/* $DESTINATION || true
+    done
+fi
+
+go get github.com/weaveworks/build-tools/cover
+cover $DESTINATION/* >profile.cov
+go tool cover -html=profile.cov -o coverage.html
+go tool cover -func=profile.cov -o coverage.txt
+tar czf coverage.tar.gz $DESTINATION