Add build action

.github/workflows/build.yml

@@ -0,0 +1,23 @@
+name: Build
+
+on: [push]
+
+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 Gradle
+      run: |
+        chmod a+x gradlew
+        ./gradlew publish
+    - uses: actions/upload-artifact@master
+      with:
+        name: jars
+        path: TerraForgedMod/build/libs