Added workflow

.github/main.yml

@@ -0,0 +1,24 @@
+name: Main Workflow
+on: [push]
+jobs:
+  build-gcc:
+    name: Build GCC
+    strategy:
+      matrix:
+        gcc-version: [5, 6, 7, 8, 9]
+    runs-on: ubuntu-latest
+    container: gcc:${{ matrix.gcc-version }}
+    steps:
+      - uses: actions/checkout@v1
+      - run: make
+  build-clang:
+    name: Build Clang
+    strategy:
+      matrix:
+        clang-version: [3, 4, 5, 6, 7]
+    runs-on: ubuntu-latest
+    container: silkeh/clang:${{ matrix.clang-version }}
+    steps:
+      - uses: actions/checkout@v1
+      - run: CC=clang make
+