Modify user annotations to reflect my own belief

Several of these changes are more descriptive additions (lines 37, 41),
however some of these changes reflect my own set of best practices I've
absorbed through the years:

* I prefer class methods to lambdas for named scopes as it allows them
    to be refactored easier, no longer relying on rails provided :scope
* String interpolation is to be preferred for creating formatted strings
    which include attributes/methods
* Command/query separation is to be adhered to as strictly as possible,
    meaning commands do not have meaningful return values, and we should
    prefer thinking about what commands "do upon success/failure" rather
    than what they "return upon success/failure"