Added name of the relation to relations info

[fenos]

This tiny PR is adding the name of the relation to the relations Object info.

Why is needed?

let's say a function accept the relation info in this way:

doSomethingWithRelation(User._joins['tasks']);

function doSomethingWithRelation(relationInfo) {
   // here i lost the name of the relation for further algorithms
}

With this PR we can access to the name of the relation

relationInfo.name