Fix the sort list function in couchdb design docs

[gnowoel]

Fixes #45.

Seems PouchDB does not recognize the sortDesc query parameter correctly. So I replaced it with descending as per this doc. Please correct me!

cc @HospitalRun/core-maintainers

[jkleinsc]

@gnowoel thanks for the PR. Unfortunately this PR causes the sorts to always be sorted ascending and this is because the "sortDesc" parameter is a special parameter used in our list functions (http://docs.couchdb.org/en/1.6.1/couchapp/ddocs.html#listfun) which is how we sort our views. Making the change to pass along "descending" causes the following to happen:

1. The view gets sorted in descending order by the key for the via (in the case of patient it is sorted descending by id)
2. The list function reverses the order of the results.

The TLDR is that the descending parameter doesn't help us because that parameter sorts on the views key, not on the order parameter passed. In order to do sorting on the order parameter, we have to pass it along to a list function which will reverse the order if sortDesc=true is passed.

[jkleinsc]

@gnowoel I misspoke a bit above... The reason I was seeing the patients always sorted in ascending order is that the views didn't get updated to recognize the changing of the parameter from sortDesc to descending. However, my point is that passing along descending=true only affects the sort order of the keys (see http://docs.couchdb.org/en/1.6.1/api/ddoc/views.html), not the columns we are trying to sort by. the list functions are using sortDesc to determine sortOrder for a column.

[gnowoel]

@jkleinsc Thanks for your detailed explanation. It really helps for me to understand the problems. I'll try to figure out a real solution.

[gnowoel]

@jkleinsc PR updated. Hope this one would work :)

[jkleinsc]

@gnowoel -- I think you have found the root of the problem! Thanks for digging into this. I think the only other thing needed on this PR is to update the version on all the views that use generateSortFunction so that all of the views get the fix. The other affected views are:
appointments_by_date
inventory_by_name

[gnowoel]

@jkleinsc Yes, I missed those two views. Thanks for pointing out. PR updated.

[jkleinsc]

@gnowoel thanks for updating! Everything looks good so I'll merge it in. Thanks again!