Add a CONTRIBUTING.md file.
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+# Contributing to Golint
+
+## Before filing an issue:
+
+### Are you having trouble building golint?
+
+Check you have the latest version of its dependencies. Run
+```
+go get -u github.com/golang/lint
+```
+If you still have problems, consider searching for existing issues before filing a new issue.
+
+## Before sending a pull request:
+
+Have you understood the purpose of golint? Make sure to carefully read `README`.
