Begin thinking about reserved names

[themeblvd]

In moving ahead with #6, and we start growing other functionality and potentially clashing endpoints we should start thinking about implementing reserved name lists.

For example, if #6 adds /first, /last and /count endpoints to querying users, we could potentially have clash because I've chosen to allow users to be queried by the username like:

/api/v1/users/<username>/

So if the following query brings back the count of users:

/api/v1/users/count/

Then, a user created named count would cause some issues.

To sum up, we need a reserved names list that will apply to usernames and article slugs when being created by the end-user. To start:

['first', 'last', 'count']