Add supported extension

index.js

@@ -2,6 +2,8 @@ module.exports = (API, projectOptions) => {
   API.chainWebpack((config) => {
     config.resolveLoader.modules.prepend(path.join(__dirname, "node_modules"));
 
+    config.resolve.extensions.prepend(".coffee");
+
     if (!projectOptions.pages) {
       config.entry("app").clear().add("./src/main.coffee");
     }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "vue-cli-plugin-coffee",
-  "version": "0.3.0",
+  "version": "0.3.1",
   "description": "CoffeeScript2 support for your @vue/cli project",
   "main": "index.js",
   "repository": {