[multi-user CI] WIP: dotty job templates, scabot conf

TODO: create a script in lampepfl/dotty with path `scripts/jobs/validate/main`,
inspired by https://github.com/scala/scala/tree/2.11.x/scripts/jobs/validate/publish-core,
that does something like:

```
baseDir=${WORKSPACE-`pwd`}
scriptsDir="$baseDir/scripts"
. $scriptsDir/common

update scala scala # note: do not do `cd ..`, so adjust your build to reflect scala/ is created in $baseDir
sbt -Ddotty.travis.build=yes update compile test scalastyle
```

Where scripts/common has:
```
update() {
  [[ -d $baseDir ]] || mkdir -p $baseDir
  cd $baseDir

  if [ ! -d $baseDir/$2 ]; then git clone "https://github.com/$1/$2.git"; fi

  cd $2

  git fetch --tags "https://github.com/$1/$2.git"
  (git fetch "https://github.com/$1/$2.git" $3 && git checkout -fq FETCH_HEAD) #|| git checkout -fq $3 # || fallback is for local testing on tag
  git reset --hard
}
```

Author: adriaanm

recipes/_master-jenkins-jobs.rb

@@ -84,6 +84,11 @@ def expandJobTemplates(user, repo, branch)
   expandJobTemplates("scala", "scala", branch)
 end
 
+# create dotty-$branch-$jobName for every template under jobs/
+%w{ master }.each do | branch |
+  expandJobTemplates("lampepfl", "dotty", branch)
+end
+
 
 # TODO #10: make a view for each top-level directory under jobs/ that lists all jobs under it (scala-2.11.x-integrate, scala-2.11.x-release, scala-2.11.x-validate)
 # https://issues.jenkins-ci.org/browse/JENKINS-8927

templates/default/jobs/lampepfl/validate/main.xml.erb

@@ -0,0 +1,23 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<project>
+<%= githubProject(
+  repoUser:    @user,
+  repoName:    "dotty",
+  repoRef:     @branch,
+  description: "PR validation",
+  nodeRestriction: "public",
+  params: [
+    {:name => "_scabot_pr", :desc => "For internal use by Scabot."}
+  ],
+  jvmVersion: 8,
+  jvmFlavor:  "oracle",
+  buildNameScript: setValidateBuildNameScript)
+%>
+  <publishers>
+    <hudson.tasks.Mailer plugin="[email protected]">
+      <recipients>[email protected]</recipients>
+      <dontNotifyEveryUnstableBuild>false</dontNotifyEveryUnstableBuild>
+      <sendToIndividuals>false</sendToIndividuals>
+    </hudson.tasks.Mailer>
+  </publishers>
+</project>

templates/default/scabot.conf.erb

@@ -13,3 +13,19 @@ scala: {
     token: "<%=@scabotVault['github']['scala']['token']%>"
   }
 }
+
+dotty: {
+  jenkins: {
+    jobSuffix: "validate-main"
+    host:  "<%=node['master']['jenkinsHost']%>"
+    user:  "<%=node['scabot']['jenkins']['user']%>"
+    token: "<%=scabotVault['jenkins']['token']%>"
+  }
+  github: {
+    repo:  "dotty"
+    branches: ["master"]
+    host:  "api.github.com"
+    user:  "lampepfl"
+    token: "<%=scabotVault['github']['lampepfl']['token']%>"
+  }
+}