add github workflows

.github/workflows/rate-limit.yml

@@ -0,0 +1,33 @@
+name: "Test rate limit"
+
+# any branch is useful for testing before a PR is submitted
+on: [push, pull_request]
+
+jobs:
+  ratelimit:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - name: docker network
+      run: docker network create --subnet=172.23.42.0/16 ep_net
+
+    - name: build docker image
+      run: |
+        docker build -f Dockerfile -t epl-debian-slim .
+        docker build -f tests/ratelimit/Dockerfile.nginx -t nginx-latest .
+        docker build -f tests/ratelimit/Dockerfile.anotherip -t anotherip .
+    - name: run docker images
+      run: |
+        docker run --name etherpad-docker -p 9000:9001 --rm --network ep_net --ip 172.23.42.2 -e 'TRUST_PROXY=true' epl-debian-slim &
+        docker run -p 8081:80 --rm --network ep_net --ip 172.23.42.1 -d nginx-latest
+        docker run --rm --network ep_net --ip 172.23.42.3 --name anotherip -dt anotherip
+
+    - name: install dependencies and create symlink for ep_etherpad-lite
+      run: bin/installDeps.sh
+
+    - name: run rate limit test
+      run: |
+        cd tests/ratelimit
+        ./testlimits.sh