Add details to credentials param in scm docs
Add details to credentials param in scm docs

The credentials-id parameter for git scm seem to be void of any details
or specifics like what exactly this parameter is, or where to get this
in jenkins. i was of opinion that its name of credential but took me a
while to fig out how to get credentials ID of a credential in jenkins.
Its actually last field of URL path when you click your credential in
 jenkins dashboard.
I have added a step-by-step github gist here:
https://gist.github.com/hayderimran7/78421229af85ae90177b
Also fixed repition of word 'create'.

Change-Id: I827779eeaae8b28f53764b70de6aaf4b80157547

lukas-bednar/jenkins-job-builder,dataxu/jenkins-job-builder,vredchenko/jenkins-job-builder,bootswithdefer/jenkins-job-builder,grdryn/jenkins-job-builder,sebbrandt87/jenkins-job-builder,michalvanco/jenkins-job-builder,CruGlobal/jenkins-job-builder,tamac-io/jenkins-job-builder,carroarmato0/jenkins-job-builder,onshape/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,joostvdg/jenkins-job-builder,wsoula/jenkins-job-builder,CruGlobal/jenkins-job-builder,sunyi00/jenkins-job-builder,puppetlabs/jenkins-job-builder,jenshnielsen/jenkins-job-builder,carroarmato0/jenkins-job-builder,maxandersen/jenkins-job-builder,onshape/jenkins-job-builder,sebbrandt87/jenkins-job-builder,klmitch/jenkins-job-builder,fuglu/jenkins-job-builder,theforeman/jenkins-job-builder,sunyi00/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,electrical/jenkins-job-builder,bootswithdefer/jenkins-job-builder,partkyle/jenkins-job-builder,mohitsethi/jenkins-job-builder,phinexus/jenkins-job-builder,dataxu/jenkins-job-builder,pyatil/jenkins-job-builder,grdryn/jenkins-job-builder,vredchenko/jenkins-job-builder,madAndroid/jenkins-job-builder,stanchan/jenkins-job-builder,linuxmaniac/jenkins-job-builder,sunyi00/jenkins-job-builder,simzacks/jjb,pyatil/jenkins-job-builder,cyberious/jenkins-job-builder,simzacks/jjb,lukas-bednar/jenkins-job-builder,twc-openstack/jenkins-job-builder,hrubi/jenkins-job-builder,electrical/jenkins-job-builder,linuxmaniac/jenkins-job-builder,twc-openstack/jenkins-job-builder,blaffoy/jenkins-job-builder,OSSystems/jenkins-job-builder,gforcada/jenkins-job-builder,jenshnielsen/jenkins-job-builder,gforcada/jenkins-job-builder,david-caro/jenkins-job-builder,klmitch/jenkins-job-builder,rsig/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,puppetlabs/jenkins-job-builder,pyatil/jenkins-job-builder,simzacks/jjb,carroarmato0/jenkins-job-builder,lukas-bednar/jenkins-job-builder,mjeanson/jenkins-job-builder,twc-openstack/jenkins-job-builder,phinexus/jenkins-job-builder,mohitsethi/jenkins-job-builder,theforeman/jenkins-job-builder,sebbrandt87/jenkins-job-builder,joostvdg/jenkins-job-builder,waynr/jenkins-job-builder,OSSystems/jenkins-job-builder,pyatil/jenkins-job-builder,grdryn/jenkins-job-builder,tya/jenkins-job-builder,onshape/jenkins-job-builder,kei-yamazaki/jenkins-job-builder,rsig/jenkins-job-builder,klmitch/jenkins-job-builder,theforeman/jenkins-job-builder,rsig/jenkins-job-builder,gforcada/jenkins-job-builder,dataxu/jenkins-job-builder,twc-openstack/jenkins-job-builder,joostvdg/jenkins-job-builder,wsoula/jenkins-job-builder,david-caro/jenkins-job-builder,gforcada/jenkins-job-builder,gforcada/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,dataxu/jenkins-job-builder,kei-yamazaki/jenkins-job-builder,linuxmaniac/jenkins-job-builder,mjeanson/jenkins-job-builder,rsig/jenkins-job-builder,phinexus/jenkins-job-builder,vredchenko/jenkins-job-builder,mjeanson/jenkins-job-builder,david-caro/jenkins-job-builder,wsoula/jenkins-job-builder,madAndroid/jenkins-job-builder,cyberious/jenkins-job-builder,kei-yamazaki/jenkins-job-builder,electrical/jenkins-job-builder,OSSystems/jenkins-job-builder,partkyle/jenkins-job-builder,linuxmaniac/jenkins-job-builder,waynr/jenkins-job-builder,hrubi/jenkins-job-builder,tamac-io/jenkins-job-builder,fuglu/jenkins-job-builder,tamac-io/jenkins-job-builder,cyberious/jenkins-job-builder,theforeman/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,tya/jenkins-job-builder,puppetlabs/jenkins-job-builder,klmitch/jenkins-job-builder,simzacks/jjb,wikimedia/integration-jenkins-job-builder,wsoula/jenkins-job-builder,OSSystems/jenkins-job-builder,puppetlabs/jenkins-job-builder,phinexus/jenkins-job-builder,mjeanson/jenkins-job-builder,CruGlobal/jenkins-job-builder,blaffoy/jenkins-job-builder,gregsymons/jenkins-job-builder,david-caro/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,onshape/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,gregsymons/jenkins-job-builder,madAndroid/jenkins-job-builder,tya/jenkins-job-builder,stanchan/jenkins-job-builder,lukas-bednar/jenkins-job-builder,phinexus/jenkins-job-builder,partkyle/jenkins-job-builder,jenshnielsen/jenkins-job-builder,stanchan/jenkins-job-builder,tamac-io/jenkins-job-builder,fuglu/jenkins-job-builder,gregsymons/jenkins-job-builder,maxandersen/jenkins-job-builder,michalvanco/jenkins-job-builder,mohitsethi/jenkins-job-builder,joostvdg/jenkins-job-builder