code: 400 error when trying to insert a new permission using Google Drive API v2
===

I'm using google-api-client (0.3.0) gem for my Rails app to access a user's data through Google Drive API v2.

I successfully searched for a file by title and then tried to use the file id from the search result to insert a new permission. I want to programmatically allow "anyone with the link" to comment on the file.

Following the sample code here:  https://developers.google.com/drive/v2/reference/permissions/insert, I wrote the following code:

    new_permission = gDriveApi.permissions.insert.request_schema.new({ 
                             'role' => "reader",
                             'type' => "anyone",
                             'value' => "",
                             'additionalRoles' => ["commenter"], 
                             'withLink' => true })

    result = client.execute(:api_method => gDriveApi.permissions.insert,
                            :body_object => new_permission,
                            :parameters => { 'fileId' => file_id })

I got a 400 error. Here is the hash dump:

    --- !ruby/object:Google::APIClient::Schema::Drive::V2::Permission 
    data: 
      error: 
        errors: 
        - domain: global reason: parseError 
          message: This API does not support parsing form-encoded input.
        code: 400 
        message: This API does not support parsing form-encoded input.

According to errors.rb in the gem source code, a 4xx error is a client error. 

Any help fixing this bug would be greatly appreciated.
