Caching .m2 repository to speed the Travis build

Signed-off-by: Doug Morato <[email protected]>

.travis.yml

@@ -6,9 +6,12 @@ install: "/bin/true"
 script:
   - mvn clean install
   - git clone https://github.com/WebGoat/WebGoat-Lessons.git
-  - mvn -file ./WebGoat-Lessons/pom.xml package
+  - mvn -file ./WebGoat-Lessons/pom.xml clean package
   - cp -fa ./WebGoat-Lessons/target/plugins/*.jar ./webgoat-container/src/main/webapp/plugin_lessons/
   - if [[ $TRAVIS_PULL_REQUEST == "false" ]]; then mvn "-Dbuild.number=$TRAVIS_BUILD_NUMBER" -Prun-integration-tests clean install; else mvn clean install; fi
+cache:
+  directories:
+  - $HOME/.m2
 before_deploy:
   - export WEBGOAT_CONTAINTER_TARGET_DIR=$HOME/build/$TRAVIS_REPO_SLUG/webgoat-container/target
   - export WEBGOAT_ARTIFACTS_FOLDER=$HOME/build/$TRAVIS_REPO_SLUG/Deployable_Artifacts/