NoMethodError when current_user is called

[jraczak]

I'm testing an API using devise_token_auth using Postman. Sign in works with no problem and returns the expected body and headers. I store the headers (I've manually verified that the correct header values are stored) and provide them in a subsequent call to create an object. In this case, it's a task. My controller builds on the current_user which should be available via devise_token_auth as I've provided the headers with the call. However, I get this error

NoMethodError (undefined method tasks' for nil:NilClass)`

which is triggered on this line

@task = current_user.tasks.create!(task_params)

What am I doing wrong? Or is this a bug?

[rmcsharry]

@jraczak If you mounted the gem at 'api' or even 'api/v1' namespace then the methods change:
current_user becomes current_api_user or even current_api_v1_user

[zachfeldman]

Potential solution posted. @jraczak feel free to reopen if it doesn't work.