diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..72d1294
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,13 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+
+[*.py]
+indent_style = space
+indent_size = 4
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..56295fe
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,17 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+## v0.2.0
+
+### Added
+
+- Added support for membership test operators (`in` and `not in`) for checking if a `date` or `datetime` falls within a `YearMonth`.
+
+### Changed
+
+- Improved `YearMonth.parse()` performance.
+
+## v0.1.0
+
+- Initial release.