change travis builds to publish docker images with tag 'nightly' (#88)

diff --git a/.travis.yml b/.travis.yml
index fba8b43..0614a19 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -47,12 +47,12 @@
       all_branches: true
       repo: apache/incubator-openwhisk-runtime-java
   - provider: script
-    script: "./tools/travis/publish.sh openwhisk 8 latest"
+    script: "./tools/travis/publish.sh openwhisk 8 nightly"
     on:
       branch: master
       repo: apache/incubator-openwhisk-runtime-java
   - provider: script
-    script: "./tools/travis/publish.sh openwhisk 8a latest"
+    script: "./tools/travis/publish.sh openwhisk 8a nightly"
     on:
       branch: master
       repo: apache/incubator-openwhisk-runtime-java
diff --git a/core/java8actionloop/Makefile b/core/java8actionloop/Makefile
index 61e98d4..a118d99 100644
--- a/core/java8actionloop/Makefile
+++ b/core/java8actionloop/Makefile
@@ -1,4 +1,4 @@
-IMG=actionloop-java-v8:latest
+IMG=actionloop-java-v8:nightly
 PREFIX=docker.io/openwhisk
 INVOKE=python ../../tools/invoke.py
 MAIN_JAR=../../example/main.jar
diff --git a/tools/travis/publish.sh b/tools/travis/publish.sh
index 26fd15f..c7bbc41 100755
--- a/tools/travis/publish.sh
+++ b/tools/travis/publish.sh
@@ -49,8 +49,8 @@
 -PdockerImagePrefix=${IMAGE_PREFIX} \
 -PdockerImageTag=${IMAGE_TAG}
 
-  # if doing latest also push a tag with the hash commit
-  if [ ${IMAGE_TAG} == "latest" ]; then
+  # if doing nightly also push a tag with the hash commit
+  if [ ${IMAGE_TAG} == "nightly" ]; then
   SHORT_COMMIT=`git rev-parse --short HEAD`
   TERM=dumb ./gradlew \
   core:${RUNTIME}:distDocker \