Added View group api

[priyanshisharma]

Fixes #107

Description

I've added the API, that provides details of a particular group of an organisation to authorised members. It can be visited at Org.views.GroupDetailsView. Test Cases and Swagger docs for the same have also been added.

Type of Change: (Delete irrelevant options)

• Code
• Testing
• Documentation

Code/Quality Assurance Only (Delete irrelevant options)

• New feature (non-breaking change which adds functionality pre-approved by mentors)

How Has This Been Tested?

Tests have been described in tests.org.tests_view_group_api.py and they run successfuly. The following is the result of executing python3 manage.py test.

----------------------------------------------------------------------
Ran 49 tests in 9.100s

OK
Destroying test database for alias 'default'...

Checklist:

• My PR follows the style guidelines of this project
• I have performed a self-review of my own code or materials
• I have commented my code or provided relevant documentation, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Any dependent changes have been merged
• Update Swagger documentation and the exported file at /docs folder
• Update requirements.txt

Code/Quality Assurance

• My changes generate no new warnings
• My PR currently breaks something (fix or feature that would cause existing functionality to not work as expected)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been published in downstream modules

[sumit-badsara]

Great work! Code seems perfect to me 🎉 ! Will test it our locally later.
Perfect usage of get() instead of filter() and catching the exception. Nice work! 👍

[naveennvrgup]

1. Great job with code quality 🎖️
2. The tests are on point. 👏 Really appreciate the use of 12345 for invalid group and org id
3. {"message":"This organization does not exist"} and similar responses can be replaced with responses.org_not_present_404 and equivalents in the view function, as it is static and increases reusability.
4. in the future error responses use detail instead of message as a key. (as per the discussion on slack 😇 )

3 & 4 are minor things so create good first issue for both of them

[naveennvrgup]

1. test locally works as expected
2. merging

[naveennvrgup]

Great work! Code seems perfect to me ! Will test it our locally later.
Perfect usage of get() instead of filter() and catching the exception. Nice work!

A approval would be better choice here 😇. Than just comment

[sumit-badsara]

Great work! Code seems perfect to me ! Will test it our locally later.
Perfect usage of get() instead of filter() and catching the exception. Nice work!

A approval would be better choice here 😇. Than just comment

Approving without testing ? 😢

[priyanshisharma]

3 & 4 are minor things so create good first issue for both of them

I've created issue #114 and #113 respectively for them. 😄