Add cmdline docs for signing and verification flows

Signed-off-by: Nathan McCauley <nathan.mccauley@docker.com>

docs/reference/commandline/cli.md

@@ -49,6 +49,8 @@ by the `docker` command line:
   unsuitable for Docker.
 * `DOCKER_RAMDISK` If set this will disable 'pivot_root'.
 * `DOCKER_TLS_VERIFY` When set Docker uses TLS and verifies the remote.
+* `DOCKER_TRUST` When set Docker uses notary to sign and verify images.
+  Equates to `--untrusted=false` for build, create, pull, push, run.
 * `DOCKER_TMPDIR` Location for temporary Docker files.
 
 Because Docker is developed using 'Go', you can also use any environment

docs/reference/commandline/create.md

@@ -61,6 +61,7 @@ Creates a new container.
       --restart="no"             Restart policy (no, on-failure[:max-retry], always)
       --security-opt=[]          Security options
       -t, --tty=false            Allocate a pseudo-TTY
+      --untrusted=true           Skip image verification
       -u, --user=""              Username or UID
       --ulimit=[]                Ulimit options
       --uts=""                   UTS namespace to use

docs/reference/commandline/pull.md

@@ -16,6 +16,7 @@ weight=1
     Pull an image or a repository from the registry
 
       -a, --all-tags=false    Download all tagged images in the repository
+      --untrusted=true        Skip image verification
 
 Most of your images will be created on top of a base image from the
 [Docker Hub](https://hub.docker.com) registry.

docs/reference/commandline/push.md

@@ -15,5 +15,7 @@ weight=1
 
     Push an image or a repository to the registry
 
+    --untrusted=true           Skip image signing
+
 Use `docker push` to share your images to the [Docker Hub](https://hub.docker.com)
 registry or to a self-hosted one.

docs/reference/commandline/run.md

@@ -65,6 +65,7 @@ weight=1
       -t, --tty=false            Allocate a pseudo-TTY
       -u, --user=""              Username or UID (format: <name|uid>[:<group|gid>])
       --ulimit=[]                Ulimit options
+      --untrusted=true           Skip image verification
       --uts=""                   UTS namespace to use
       -v, --volume=[]            Bind mount a volume
       --volumes-from=[]          Mount volumes from the specified container(s)