diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..57cf099
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,12 @@
+# Version 0.10.0 (2021-04-03)
+
+This is the first version of the Kosmorrolib.  It is numbered "0.10.0" because directly follows the version 0.9.0 of the Kosmorro project.
+
+### Bug Fixes
+
+* take the timezone in account on get_moon_phase ([2df588e](https://github.com/Kosmorro/lib/commit/2df588e5c13246c19b3b5828bdf58b95d11ec104))
+
+
+### Features
+
+* make the date parameter optional (default value: today) ([c59b553](https://github.com/Kosmorro/lib/commit/c59b553c86999958027a7649c52811b2bc5162fd))
diff --git a/Makefile b/Makefile
index 51f5257..b25d2a4 100644
--- a/Makefile
+++ b/Makefile
@@ -34,8 +34,8 @@ tag: env
 	git commit -m "build: bump version $$RELEASE_NUMBER"
 	git tag "v$$RELEASE_NUMBER"
 	git checkout features
-	git merge master
-	git checkout master
+	git merge main
+	git checkout main
 
 	@echo
 	@echo -e "\e[1mVersion \e[36m$$RELEASE_NUMBER\e[39m successfully tagged!"