Update README.md

Author: jonathancadepowers

README.md

@@ -7,6 +7,18 @@ Climate's hosted, automated code review service. Based on SimpleCov.
 
 Code Climate - [https://codeclimate.com](https://codeclimate.com)
 
+# Important FYIs
+
+Across the many different testing frameworks, setups, and environments, there are lots of variables at play. Before setting up test coverage, it's important to understand what we do and do not currently support:
+
+* **Default branch only:** We only support test coverage for your default branch. Be sure to check out this branch before running your tests.
+* **Single payload:** We currently only support a single test coverage payload per commit. If you run your tests in multiple steps, or via parallel tests, Code Climate will only process the first payload that we receive. If you are using a CI, be sure to check if you are running your tests in a parallel mode.
+
+  **Note:** There is one exception to this rule. We've specifically built an integration with Solano Labs to support parallel tests.
+
+  **Note:** If you've configured Code Climate to analyze multiple languages in the same repository (e.g., Ruby and JavaScript), we can nonetheless only process test coverage information for one of these languages. We'll process the first payload that we receive.
+* **Invalid File Paths:** By default, our test reporters expect your application to exist at the root of your repository. If this is not the case, the file paths in your test coverage payload will not match the file paths that Code Climate expects. For our Ruby test reporter, [we have a work-around to this issue](http://docs.codeclimate.com/article/220-help-im-having-trouble-with-test-coverage#ruby_sub_folder).
+
 ## Installation
 
 This gem requires a user, but not necessarily a paid account, on Code Climate, so if you don't have one the
@@ -57,6 +69,10 @@ end
 CodeClimate::TestReporter.start
 ```
 
+## Troubleshooting
+
+If you're having trouble setting up or working with our test coverage feature, [see our detailed help doc](http://docs.codeclimate.com/article/220-help-im-having-trouble-with-test-coverage), which covers the most common issues encountered.
+
 ## Extending Simplecov with other formatters
 
 Since ruby-test-reporter 0.4.0 you can use `CodeClimate::TestReporter::Formatter` as a Simplecov formatter directly. Just add the formatter to your Simplecov formatter in addition to the rest of your configuration: