[#592] Adding release notes for 2.3.7
[#592] Updating with correct release date
Merge pull request #593 from akvo/feature/592-releasenotes

Feature/592 releasenotes - all good and correct! Great work @rumca
Merge pull request #598 from akvo/develop

Merge [#589] for 2.3.7 release
Merge branch 'release/candidate' of github.com:akvo/akvo-rsr
Merge pull request #602 from akvo/master

[#592] Adding release notes for 2.3.7