README.md in br_danfe-0.7.2 vs README.md in br_danfe-0.7.3

@@ -4,11 +4,11 @@
 
 This gem generates PDF files for Brazilian DANFE (_Documento Auxiliar da Nota Fiscal Eletrônica_) from a valid NF-e XML. It also can generates PDF file for CC-e (_Carta de Correção Eletrônica_).
 
 [See an example here.](https://github.com/asseinfo/br_danfe/blob/master/spec/fixtures/v2.00/nfe_with_logo.xml.fixture.pdf?raw=true)
 
-This gem requires `ruby >= 1.9.3`.
+This gem requires `ruby >= 2.0`.
 
 ## Supported NF-e versions
 
 XML version | Supported?
 ----------- | ----------
@@ -104,9 +104,21 @@
 ## About tests
 
 > If you modify something that caused general visual changes at output pdf's, so you have to rebuild the fixtures pdf files.
 >
 > You can do this simply deleting the fixture pdf file. The `have_same_content_of` matcher will recreate the fixture in the next time you run the `bundle exec rspec` command.
+
+
+## Environment variables
+
+The following variables are necessary to be set:
+
+Environment var       | Development? | Test? | CI?   | Production? | Data
+----------------------|--------------|-------|-------|-------------|-----
+TZ                    | no           | no    | yes   | no          | America/Sao_Paulo 
+BUNDLE_PATH           | no           | no    | yes   | no          | vendor/bundle 
+CC_TEST_REPORTER_ID   | no           | no    | yes   | no          | get at codeclimate 
+RAILS_ENV             | no           | no    | yes   | no          | test  
 
 ### Code coverage
 
 Code coverage is available through of SimpleCov. Just run `bundle exec rspec` and open the coverage report in your browser.