Users allowed to submit incomplete 'Add API' form

[saralavanip]

Steps:
1.Visit https://nightly.apinf.io
2.Create account clicking on Signup
3.Go to API Backends
4.Click on 'Add API Backend'
5.Enter Details:

• Enter API name
• Do not enter 'Description' (empty field)
• Do not enter URL

6.Click on 'Add API' button

Findings:

• Successful in adding API without filling 'Description' and 'URL fields'
• Users not notified if fields empty

[brylie]

After discussing with @saralavanip and @bajiat, we decided to make the URL field mandatory. This has been done in commit ac2b686