Create github action files for CI/CD Action

Author: CihatAltiparmak

.github/workflows/backend.yml

@@ -0,0 +1,15 @@
+name: Backend CI/CD
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+    - name: Build and test
+      run: mvn clean install