1 files changed, 36 insertions, 0 deletions
diff --git a/doc/contributing/making_changes_to_ruby.md b/doc/contributing/making_changes_to_ruby.md
new file mode 100644
index 0000000000..6842ec2888
--- /dev/null
+++ b/doc/contributing/making_changes_to_ruby.md
@@ -0,0 +1,36 @@
+# Contributing a pull request
+
+## Code style
+
+Here are some general rules to follow when writing Ruby and C code for CRuby:
+
+* Do not change code unrelated to your pull request (including style fixes)
+* Indent 4 spaces for C without tabs (tabs are two levels of indentation, equivalent to 8 spaces)
+* Indent 2 spaces for Ruby without tabs
+* ANSI C style for function declarations
+* Follow C99 Standard
+* PascalStyle for class/module names
+* UNDERSCORE_SEPARATED_UPPER_CASE for other constants
+* Abbreviations should be all upper case
+
+## Commit messages
+
+Use the following style for commit messages:
+
+* Use a succinct subject line
+* Include reasoning behind the change in the commit message, focusing on why the change is being made
+* Refer to  issue (such as `Fixes [Bug #1234]` or `Implements [Feature #3456]`), or discussion on the mailing list (such as [ruby-core:12345])
+
+## CI
+
+GitHub actions will run on each pull request.
+
+There is [a CI that runs on master](https://rubyci.org/). It has broad coverage of different systems and architectures, such as Solaris SPARC and macOS.
+
+# Contributing to standard libraries
+
+Everything in the [lib](https://github.com/ruby/ruby/tree/master/lib) directory is mirrored from a standalone repository into the Ruby repository.
+If you'd like to make contributions to standard libraries, do so in the standalone repositories, and the
+changes will be automatically mirrored into the Ruby repository.
+
+For example, CSV lives in [a separate repository](https://github.com/ruby/csv) and is mirrored into [Ruby](https://github.com/ruby/ruby/tree/master/lib/csv).