Add SwaggerConfiguration class

SwaggerConfiguration class as its name is responsible to provide general information regarding the API.

gh-19
Add API information and update path for create and update

Add a more human words describing the API. Changes to the path is because swagger is unable to discover path operation that is being defined without value or an empty string as value.

gh-19
Fix error in executing repository test

Annotate UserRepositoryTest with @WebAppConfiguration to avoid servlet exception.

Closes gh-19