updated key concept (#3959)
updated key concept (#3959)

docker service, will run on the manager or worker. Last file contains only worker.
londoncalling/docker.github.io,JimGalasyn/docker.github.io,anweiss/docker.github.io,londoncalling/docker.github.io,shin-/docker.github.io,docker/docker.github.io,londoncalling/docker.github.io,shin-/docker.github.io,anweiss/docker.github.io,shin-/docker.github.io,londoncalling/docker.github.io,docker/docker.github.io,shubheksha/docker.github.io,thaJeztah/docker.github.io,shubheksha/docker.github.io,shin-/docker.github.io,shubheksha/docker.github.io,johnstep/docker.github.io,londoncalling/docker.github.io,anweiss/docker.github.io,docker/docker.github.io,anweiss/docker.github.io,thaJeztah/docker.github.io,JimGalasyn/docker.github.io,JimGalasyn/docker.github.io,JimGalasyn/docker.github.io,docker/docker.github.io,johnstep/docker.github.io,thaJeztah/docker.github.io,johnstep/docker.github.io,shin-/docker.github.io,anweiss/docker.github.io,johnstep/docker.github.io,docker/docker.github.io,shubheksha/docker.github.io,thaJeztah/docker.github.io,JimGalasyn/docker.github.io,shubheksha/docker.github.io,thaJeztah/docker.github.io,johnstep/docker.github.io