Add .drone.yml for continuous integration on Drone CI.

.drone.yml

@@ -0,0 +1,14 @@
+kind: pipeline
+name: default
+
+steps:
+  - name: prepare
+    image: node:12
+    commands:
+      - npm install
+  - name: build
+    image: node:12
+    environment:
+      NPMPATH: "node_modules/.bin"
+    commands:
+      - $NPMPATH/grunt

.editorconfig

@@ -9,5 +9,7 @@ charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
 
+[*.yml]
+indent_size = 2
 [*.md]
 trim_trailing_whitespace = false