#161911732 signin endpoint

[mnswaleh]

What does this PR do?

Enables users to signin

Description of Task to be completed?

should have:

1. endpoint test
2. model function to verify user details
3. signin endpoint

How should this be manually tested?

1. on postman enter url, http://127.0.0.1:5000/api/v1/users/signin
2. send a post request with username and password
3. if user details add up you should receive user details

What are the relevant pivotal tracker stories?

#161911732

Screenshots (if appropriate)

[coveralls]

Pull Request Test Coverage Report for Build 53

• 112 of 131 (85.5%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+2.6%) to 93.699%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
app/api/v1/models/users_model.py	6	7	85.71%
app/api/v1/views/users_view.py	32	33	96.97%
app/api/v1/models/orders_model.py	31	48	64.58%

Totals
Change from base Build 17:	2.6%
Covered Lines:	342
Relevant Lines:	365

---

💛 - Coveralls