Fix for pagination ‘last’ link to give the real last page

[yanivp]

We're working on a project using django-json-api and came across unintuitive behavior for the pagination. The current pagination implementation for the 'last' link is basically a 'total count' - 'limit'. Consider the following example:

Objects = [0-21]
Limit = 10
(first page - offset 0)
0,1,2,3,4,5,6,7,8,9

(clicking 'next' - offset 10)
10,11,12,13,14,15,16,17,18,19

(clicking 'next' - offset 20)
20,21

(clicking 'last' - offset 12)
12,13,14,15,16,17,18,19,20,21

This behavior would make the user completely disoriented in the paging. It makes more sense that 'last' will offset to 20 just the same as clicking 'next'->'next'->'next' and simply return two objects instead of 10.

[mblayman]

Hi, @yanivp. Thanks for your contribution! It looks like you're a first time contributor so I'm excited that you took the time to help.

The PR, in its current state, can't be merged because the test suite is reporting failure (you can use the error at https://travis-ci.org/django-json-api/django-rest-framework-json-api/builds/235614695?utm_source=github_status&utm_medium=notification). Either the fix is not quite correct and the tests are saving us from making a mistake, or the test is not correct. Could you please look into what the issue is?

Also, please add your name to the AUTHORS file to give you some credit for your contribution. The listing is alphabetical by first name.

Let me know if you have any questions. Thanks again!

[yanivp]

Hey @mblayman
You're right I forgot to run the tests, fixed and also added myself to AUTHORS

[codecov-io]

Codecov Report

Merging #353 into develop will decrease coverage by 0.02%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop     #353      +/-   ##
===========================================
- Coverage    77.09%   77.06%   -0.03%     
===========================================
  Files           50       50              
  Lines         6026     6027       +1     
===========================================
- Hits          4646     4645       -1     
- Misses        1380     1382       +2

Impacted Files	Coverage Δ
rest_framework_json_api/pagination.py	54.81% <100%> (ø)	⬆️
example/tests/unit/test_pagination.py	100% <100%> (ø)	⬆️
example/models.py	66.95% <0%> (-0.13%)	⬇️

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[mblayman]

👍 Good stuff. Thank you!