Add database migration script
Remove database migration script

Not needed anymore since the migration has been applied.
Move time handling completely into logger class
Simplify log message
Improve logger tests
Refactor logger class methods for (recent) entries

Move logic into #entries; return an array of log messages.
Fix test for failing send process

Be more specific about the expected response body,
an "Internal Server Error" should make the test fail.
Introduce specialized logging methods
Add test for handling of missing request parameters
Add rake task for retrieving email service stats
Add mailer class and rake task for email delivery test
Set local time zone to UTC

Workaround for the correct retrieval of times from the database:
DataMapper stores times into PostgreSQL as UTC but retrieves them
as times in the local time zone.
Add db table for daily stats and rake task for log entry migration
Always use double quotes
Remove unnecessary require statement

Requiring minitest/autorun also loads minitest/spec.
Use Ruby 2.1.3
Update gem bundle
Use Ruby 2.1.5
Add rake task to list all failed requests