Use Simple Token Authentication v1.7.0 or higher for out-of-the-box Rails::API support

[gonzalo-bulnes]

Simple Token Authentication v1.7.0 does support Rails::API! That means this line can be removed form the ApplicationController definition.

Let's mention that there is not reason not to use Simple Token Authentication v1.7.0, since it is backward compatible with v1.6.0 (see #1).

[Deleted user]

62d7c94