add docs

Signed-off-by: Victor Vieux <vieux@docker.com>

daemon/exec.go

@@ -64,7 +64,7 @@ func (e *execStore) Delete(id string) {
 func (e *execStore) List() []string {
 	var IDs []string
 	e.RLock()
-	for id, _ := range e.s {
+	for id := range e.s {
 		IDs = append(IDs, id)
 	}
 	e.RUnlock()

docs/sources/reference/api/docker_remote_api.md

@@ -51,6 +51,11 @@ You can still call an old version of the API using
 **New!**
 Docker client now hints potential proxies about connection hijacking using HTTP Upgrade headers.
 
+`GET /containers/(id)/json`
+
+**New!**
+This endpoint now returns the list current execs associated with the container (`ExecIDs`).
+
 ## v1.16
 
 ### Full Documentation

docs/sources/reference/api/docker_remote_api_v1.17.md

@@ -310,6 +310,9 @@ Return low-level information on the container `id`
                      "SysInitPath": "/home/kitty/go/src/github.com/docker/docker/bin/docker",
                      "ResolvConfPath": "/etc/resolv.conf",
                      "Volumes": {},
+                     "ExecIDs": [
+                         "15f211491dced6a353a2e0f37fe3f3692ee2370a4782418e9bf7052865c10fde"
+                     ],
                      "HostConfig": {
                          "Binds": null,
                          "ContainerIDFile": "",