Add Gemfile.lock missed from earlier commit
Make save failure error reporting more robust

Be sure to log an error even if there are no extra details.
Fix tests for DST

With the DST support from datainsight_recorder 0.4.1 datetimes are in
local time for Europe/London.
Merge pull request #10 from alphagov/fix-for-dst

Fix tests for DST support in backdrop_recorder 0.4.1