modified a little sql to make it work with postgres https://github.com/iRessources/AgileDwarf/issues/9#issuecomment-7490537 (needs to be refined further to be platform independent); modified burndown.js according to https://github.com/iRessources/AgileDwarf/issues/36#issuecomment-9974392 also fixed incorrect case of issueId to issueid
Merge branch 'port_to_postgres' of https://github.com/spaceshipoperator/AgileDwarf
Fixing merge regressions.
Mixed solution for the #47

The ricemery's implementation [1] worked (Sprints view), but [2] failed (Tasks view) in my pgsql install. The workaround in [3] requires additional db requests (AFAIK), but is working.

So, this is a mixed solution, using [1] for Sprints and [3] for Tasks.

[1] https://github.com/ricemery/AgileDwarf/commit/2bf7a3fc138d39edfd0de7f7619eba432c378fbc
[2] https://github.com/ricemery/AgileDwarf/commit/2fe8c22e3efc286ec8452c1394396f3ebe63a731
[3] https://github.com/tavlima/AgileDwarf/commit/8ff614400b0b5f2e8310c68a2440975568413f12