Merge pull request #1 from mbrookes/modularise

Modularise scopes.rb into respective databases
Add Mysql2 to supported adapters
Merge pull request #2 from mbrookes/patch-1

Add Mysql2 to supported adapters
where() condition to exclude null dates.
Update README.md

Move sqlite support to the top of the list of differences with groupdate, as this is the key differentiator. Mention that the output format is different.
Added an example where you can limit the range
Added in different aggregation functions
Merge pull request #4 from mbrookes/patch-1

where() condition to exclude null dates.
Merge pull request #5 from mbrookes/patch-2

Update README.md
Updated a version and expanded documentation
sql type in readme
merge upstream/master into output_format
Update README for new default format, and configuration option