add github actions pull request verification (#1)

.github/workflows/maven.yml

diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
new file mode 100644
index 0000000..b4580b4
--- /dev/null
+++ b/.github/workflows/maven.yml
@@ -0,0 +1,20 @@
+name: Java CI
+
+on:
+  pull_request:
+    branches:
+    - master
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+    - name: Build with Maven
+      run: mvn package --file pom.xml