Create a helper function which returns a Models instance containing the mock models only.

For ease of use, we also add a New() method which returns a Models struct containing the initialized MovieModel and initialized UserModel.

ValidateTokenPlaintext checks that the plaintext token has been provided and is exactly 26 bytes long.

Define constants for the token scope.

Define constants for the token scope.

Define constants for the token scope.

Define a custom ErrRecordNotFound error.

Define an error that our UnmarshalJSON() method can return if we're unable to parse or convert the JSON string successfully.

Define a custom ErrRecordNotFound error.

Metadata holds the pagination metadata.

Create a Models struct which wraps the MovieModel.

Annotate the Movie struct with struct tags to control how the keys appear in the JSON-encoded output.

Define a MovieModel struct type which wraps a sql.DB connection pool.

PermissionModel struct type which wraps a sql.DB connection pool.

Token holds the data for an individual token.

TokenModel struct wraps the connection pool.

User struct represents an individual user.

UserModel struct wraps the connection pool.

Define a Permissions slice, which we will use to will hold the permission codes (like "movies:read" and "movies:write") for a single user.

Declare a custom Runtime type, which has the underlying type int32 (the same as our Movie struct field).