keep path of source file in source map (#895)

Author: Elevista

lib/selector.js

@@ -9,7 +9,8 @@ var loaderUtils = require('loader-utils')
 module.exports = function (content) {
   this.cacheable()
   var query = loaderUtils.getOptions(this) || {}
-  var filename = path.basename(this.resourcePath)
+  var context = (this._compiler && this._compiler.context) || this.options.context || process.cwd()
+  var filename = path.relative(context, this.resourcePath).replace(/\..+$/, '.vue')
   var parts = parse(content, filename, this.sourceMap)
   var part = parts[query.type]
   if (Array.isArray(part)) {