add ROIMB4 conformance rule

on `BaseRegulation`
>The referenced regulation group must exist
Merge pull request #165 from bitzesty/ROIMB4

add ROIMB4 conformance rule
Add Contributing and Licence sections to README

Also update the ruby version to 2.0.0 and include the other repos used by the tariff.
Remove double locking
Merge pull request #163 from bitzesty/sync_improvements

Sync improvements - addresses issue #69915038 (PT)
Add filesize and applied_at column

Requested at #69886330 (PT)
Merge pull request #167 from bitzesty/additional_info_for_uploads

Add filesize and applied_at column
Merge pull request #166 from bitzesty/GA4

add GA4 conformance rule
add GA5 conformance rule

on `GeographicalArea`
>If a geographical area has a parent geographical area group then the validity period of the parent geographical area group must span the validity period of the geographical area.

It won't complain if dates aren't present
add GA6 conformance rule

In `GeographicalArea`
>Loops in the parent relation between geographical areas and parent geographical area groups are not allowed. If a geographical area A is a parent geographical area group of B then B cannot be a parent geographical area group of A (loops can also exist on more than two levels, e.g. level 3; If A is a parent of B and B is a parent of C then C cannot be a parent of A).