Parallel testing

Jenkinsfile

@@ -15,7 +15,8 @@ pipeline {
                     //def implementations = sh(script: 'docker run retropikzel1/compile-r7rs:chibi sh -c "compile-r7rs --list-r7rs-schemes"', returnStdout: true).split()
                     def implementations = "chibi chicken gauche guile kawa mosh racket sagittarius stklos ypsilon".split()
 
-                    implementations.each { implementation->
+                    parallel implementations.collectEntries { implementation->
+                        [(implementation): {
                                 stage("${implementation} install") {
                                     catchError(buildResult: 'SUCCESS', stageResult: 'FAILURE') {
                                         sh "docker build --build-arg SCHEME=${implementation} --tag=r7rs-pffi-test-${implementation} -f dockerfiles/Dockerfile.snow-chibi-install-test ."
@@ -31,6 +32,8 @@ pipeline {
                                     }
                                 }
                             }
+                        ]
+                    }
                 }
             }
         }