The file uploader file input should accept .sb files as well.

Author: kchadha

src/containers/sb-file-uploader.jsx

@@ -101,7 +101,7 @@ class SBFileUploader extends React.Component {
     renderFileInput () {
         return (
             <input
-                accept=".sb2,.sb3"
+                accept=".sb,.sb2,.sb3"
                 ref={this.setFileInput}
                 style={{display: 'none'}}
                 type="file"