Add Ability to Toggle Posts as Answered Vs. Unanswered

[katcday]

• Updated Yaml files src/posts/data.js and src/posts/data.js to include new field in Jsons.
• Updated src/api/posts.js to include an answer and unanswer API function.
• Updated src/controllers/write/posts.js to include answer and unanswer functions that call their API counterparts and format the response.
• Created src/posts/answer.js to handle the toggling logic and the logic of the API functions.
• Created an event in public/src/client/topic/events.js which will handle UI change in next PR.
• Added a test case to test/posts.js

resolves #3

[coveralls]

Pull Request Test Coverage Report for Build 11025214522

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 17 of 25 (68.0%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.008%) to 82.658%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/api/posts.js	3	4	75.0%
src/posts/answer.js	10	11	90.91%
src/controllers/write/posts.js	2	8	25.0%

Totals
Change from base Build 11001689541:	-0.008%
Covered Lines:	22340
Relevant Lines:	25607

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💛 - Coveralls

[KesterTan]

LGTM, flow works well and API call is working as expected