shopify_theme

Merge pull request #151 from gavinballard/add_oauth_token_support

Update README and CHANGELOG for new OAuth changes.

Simplify Shopify API authentication strategy to always use header-based authentication with either a private application password or an OAuth access token.

Add ignore for JetBrains-based editors.

Add support for API authentication via OAuth token, specified in config.yml by `:token:`.