drone: Only push master to production

.drone.yml

@@ -12,7 +12,10 @@ steps:
     commands:
       - nix build -L
 
-  - name: push
+  - name: push-prod
+    when:
+      branch:
+        - master
     environment:
       NETLIFY_AUTH_TOKEN:
         from_secret: netlify_auth_token
@@ -20,3 +23,16 @@ steps:
       - cp --no-preserve=mode -rL result netlify-does-not-follow-symlinks
       - nix develop -c netlify deploy --prod -d netlify-does-not-follow-symlinks
       - rm -rf netlify-does-not-follow-symlinks
+
+  - name: push-staging
+    when:
+      branch:
+        exclude:
+          - master
+    environment:
+      NETLIFY_AUTH_TOKEN:
+        from_secret: netlify_auth_token
+    commands:
+      - cp --no-preserve=mode -rL result netlify-does-not-follow-symlinks
+      - nix develop -c netlify deploy -d netlify-does-not-follow-symlinks
+      - rm -rf netlify-does-not-follow-symlinks