in your case, everything seems to be fine signature wise on your system.
Now, the Ign you see are for InRelease files, because APT falls back to Release files a few lines later.
I don't know why you don't see the docker-engine package. Are you perhaps running i386? The docker package is only provided for amd64. You should also see the heroku-toolbelt package.
Finally, your system seems a bit messed up. Please delete the files in /var/lib/apt/lists/partial, as there seems to be some permission issue.
Hi Fabio,
in your case, everything seems to be fine signature wise on your system.
Now, the Ign you see are for InRelease files, because APT falls back to Release files a few lines later.
I don't know why you don't see the docker-engine package. Are you perhaps running i386? The docker package is only provided for amd64. You should also see the heroku-toolbelt package.
Finally, your system seems a bit messed up. Please delete the files in /var/lib/ apt/lists/ partial, as there seems to be some permission issue.