Add Branch alias

Some branches have a "/" in their name (e.g. feature/new-and-cool)
Some commands, such as those tha deal with directories, don't
play nice with this naming convention. Define an alias for the
branch name that can be used in these scenarios.

Jenkinsfile

@@ -5,6 +5,16 @@ pipeline {
         // building the Docker image.
         disableConcurrentBuilds()
     }
+    environment {
+        // Some branches have a "/" in their name (e.g. feature/new-and-cool)
+        // Some commands, such as those tha deal with directories, don't
+        // play nice with this naming convention.  Define an alias for the
+        // branch name that can be used in these scenarios.
+        BRANCH_ALIAS = sh(
+            script: 'echo $BRANCH_NAME | sed -e "s#/#_#g"',
+            returnStdout: true
+        ).trim()
+    }
     stages {
         // Run the build in the against the dev branch to check for compile errors
         stage('Run Integration Tests') {
@@ -18,13 +28,13 @@ pipeline {
             steps {
                 echo 'Building Test Docker Image'
                 sh 'cp test/Dockerfile.test Dockerfile'
-                sh 'docker build --target voigt_kampff -t mycroft-core:latest .'
+                sh 'docker build --target voigt_kampff -t mycroft-core:${BRANCH_ALIAS} .'
                 echo 'Running Tests'
                 timeout(time: 10, unit: 'MINUTES')
                 {
                     sh 'docker run \
                         -v "$HOME/voigtmycroft:/root/.mycroft" \
-                        mycroft-core:latest'
+                        mycroft-core:${BRANCH_ALIAS}'
                 }
             }
         }