attach support
attach support

Signed-off-by: Victor Vieux <ce584ac70734cfa5a848cd28039798932c7ea675@docker.com>

mavenugo/swarm,danix800/docker.github.io,BSWANG/swarm,rutulpatel/swarm,FollowMyDev/swarm,ch3lo/swarm,linecheng/swarm,alexisbellido/docker.github.io,francisbouvier/swarm,srikalyan/swarm,jimmyxian/swarm,alexisbellido/docker.github.io,deis/swarm,mgoelzer/swarm,JimGalasyn/docker.github.io,LuisBosquez/docker.github.io,thaJeztah/docker.github.io,vlajos/swarm,docker-zh/docker.github.io,LuisBosquez/docker.github.io,shin-/docker.github.io,LuisBosquez/docker.github.io,rillig/docker.github.io,JimGalasyn/docker.github.io,SivagnanamCiena/swarm,rancher/swarm,johnstep/docker.github.io,shot/swarm,tranceitionalMynd/swarm,MHBauer/swarm,shin-/docker.github.io,zkcrescent/swarm,BSWANG/denverdino.github.io,joeuo/docker.github.io,aduermael/docker.github.io,ezrasilvera/swarm,anweiss/docker.github.io,BSWANG/denverdino.github.io,denverdino/denverdino.github.io,barais/swarm,bdwill/docker.github.io,Aorjoa/swarm,Aorjoa/swarm,phiroict/docker,tnachen/swarm,beni55/swarm-1,mountkin/swarm,aduermael/docker.github.io,schmunk42/swarm,mrjana/swarm,londoncalling/docker.github.io,denverdino/denverdino.github.io,shin-/docker.github.io,rav121/swarm,chanwit/swarm,unodba/swarm,aidora/pisces,LuisBosquez/docker.github.io,gdevillele/docker.github.io,iaintshine/swarm,yp-engineering/swarm,beni55/swarm-1,jzwlqx/denverdino.github.io,ezrasilvera/swarm,dnephin/swarm,ejholmes/swarm,rutulpatel/swarm,moxiegirl/swarm,thaJeztah/docker.github.io,gonkulator/swarm,anweiss/docker.github.io,ricca742/swarm,adouang/swarm,docker-zh/docker.github.io,gonkulator/swarm,jzwlqx/denverdino.github.io,ch3lo/swarm,BSWANG/denverdino.github.io,jeffjen/swarm,liubin/swarm,swarm-hooks/swarm,bpradipt/swarm,ehazlett/swarm,mavenugo/swarm,anweiss/docker.github.io,troy0820/docker.github.io,sanscontext/docker.github.io,docker/docker.github.io,francisbouvier/swarm,riuvshin/swarm,troy0820/docker.github.io,rajdeepd/swarm,raoofm/swarm,jimmycmh/swarm,u2mejc/swarm,alexisbellido/docker.github.io,xFragger/swarm,swarm-hooks/swarm,CodeNow/swarm,dims/swarm,docker-zh/docker.github.io,aidora/pisces,phiroict/docker,affo/swarm,jdamick/swarm,akerbis/armhf-swarm,zkcrescent/swarm,docker/docker.github.io,ricca742/swarm,kyhavlov/swarm,jay-lau/swarm,schmunk42/swarm,jimenez/swarm,mrjana/swarm,christophelec/swarm,gradywang/swarm,affo/swarm,jimenez/swarm,tnachen/swarm,docker-zh/docker.github.io,troy0820/docker.github.io,shubheksha/docker.github.io,PeoplePerHour/libswarm,sfsmithcha/swarm,denverdino/swarm-1,iaintshine/swarm,shubheksha/docker.github.io,CiaranCostello/swarm,anweiss/docker.github.io,thaJeztah/docker.github.io,adouang/swarm,allencloud/swarm,gradywang/swarm,cgvarela/swarm,errordeveloper/swarm,shubheksha/docker.github.io,sanscontext/docker.github.io,shakamunyi/swarm,phiroict/docker,shin-/docker.github.io,shot/swarm,jzwlqx/denverdino.github.io,morpheyesh/swarm,thaJeztah/docker.github.io,denverdino/docker.github.io,abronan/swarm,SivagnanamCiena/swarm,xFragger/swarm,cgvarela/swarm,gdevillele/docker.github.io,megamsys/swarm,denverdino/docker.github.io,tangkun75/swarm,auzias/swarm,menglingwei/denverdino.github.io,rav121/swarm,akerbis/armhf-swarm,denverdino/denverdino.github.io,menglingwei/denverdino.github.io,FollowMyDev/swarm,snrism/swarm,danix800/docker.github.io,londoncalling/docker.github.io,marsmensch/swarm,therealbill/swarm,bpradipt/swarm,docker/docker.github.io,fugr/swarm,shahankhatch/swarm,rajdeepd/swarm,bdwill/docker.github.io,therealbill/swarm,snrism/swarm,gdevillele/docker.github.io,LukasBacigal/swarm,shahankhatch/swarm,rchicoli/swarm,ezrasilvera/SwarmACLs,rchicoli/swarm,joaofnfernandes/docker.github.io,pdevine/swarm,atlassian/swarm,shakamunyi/swarm,jimmycmh/swarm,raoofm/swarm,shin-/docker.github.io,menglingwei/denverdino.github.io,aduermael/docker.github.io,denverdino/denverdino.github.io,marsmensch/swarm,phiroict/docker,errordeveloper/swarm,NunoEdgarGub1/swarm,johnstep/docker.github.io,sanscontext/docker.github.io,vlajos/swarm,shubheksha/docker.github.io,thaJeztah/docker.github.io,jay-lau/swarm,anweiss/docker.github.io,doronp/swarm,abronan/swarm,JimGalasyn/docker.github.io,sanscontext/docker.github.io,ehazlett/swarm,deis/swarm,troy0820/docker.github.io,ealang/swarm,mgoelzer/swarm,jzwlqx/denverdino.github.io,JimGalasyn/docker.github.io,denverdino/denverdino.github.io,jzwlqx/denverdino.github.io,everett-toews/swarm,BSWANG/denverdino.github.io,moxiegirl/swarm,danix800/docker.github.io,morpheyesh/swarm,BSWANG/swarm,kyhavlov/swarm,fugr/swarm,joaofnfernandes/docker.github.io,atlassian/swarm,rillig/docker.github.io,denverdino/swarm-1,bsmr-docker/swarm,NunoEdgarGub1/swarm,chanwit/swarm,johnstep/docker.github.io,parapsyche/swarm,denverdino/docker.github.io,alexisbellido/docker.github.io,jimmyxian/swarm,doronp/swarm,cpuguy83/swarm,bdwill/docker.github.io,joeuo/docker.github.io,rancher/swarm,denverdino/docker.github.io,gdevillele/docker.github.io,londoncalling/docker.github.io,CiaranCostello/swarm,jeffjen/swarm,joaofnfernandes/docker.github.io,mountkin/swarm,londoncalling/docker.github.io,denverdino/swarm,qianzhangxa/swarm,CodeNow/swarm,ejholmes/swarm,Spritekin/swarm,danix800/docker.github.io,aduermael/docker.github.io,johnstep/docker.github.io,krystism/swarm,ealang/swarm,Spritekin/swarm,cpuguy83/swarm,menglingwei/denverdino.github.io,JimGalasyn/docker.github.io,echupriyanov/swarm,johnstep/docker.github.io,polyverse-security/swarm,denverdino/docker.github.io,LuisBosquez/docker.github.io,joaofnfernandes/docker.github.io,barais/swarm,FreedomWangLi/swarm,yp-engineering/swarm,u2mejc/swarm,joaofnfernandes/docker.github.io,EderRoger/swarm,shubheksha/docker.github.io,tangkun75/swarm,jdamick/swarm,pssahi/swarm,joeuo/docker.github.io,phiroict/docker,krystism/swarm,everett-toews/swarm,joeuo/docker.github.io,linecheng/swarm,docker/docker.github.io,ezrasilvera/SwarmACLs,denverdino/swarm,tranceitionalMynd/swarm,megamsys/swarm,joeuo/docker.github.io,FreedomWangLi/swarm,alexisbellido/docker.github.io,kunalkushwaha/swarm,pssahi/swarm,LukasBacigal/swarm,resouer/swarm,qianzhangxa/swarm,dims/swarm,docker/docker.github.io,srikalyan/swarm,polyverse-security/swarm,rillig/docker.github.io,EderRoger/swarm,christophelec/swarm,menglingwei/denverdino.github.io,echupriyanov/swarm,resouer/swarm,pdevine/swarm,londoncalling/docker.github.io,dnephin/swarm,MHBauer/swarm,liubin/swarm,gdevillele/docker.github.io,kunalkushwaha/swarm,PeoplePerHour/libswarm,allencloud/swarm,BSWANG/denverdino.github.io,bsmr-docker/swarm,sanscontext/docker.github.io,bdwill/docker.github.io,rillig/docker.github.io,docker-zh/docker.github.io,sfsmithcha/swarm,unodba/swarm,riuvshin/swarm,parapsyche/swarm,bdwill/docker.github.io,auzias/swarm