chore: add Makefile to automate the release process

.editorconfig

@@ -11,3 +11,6 @@ trim_trailing_whitespace = true
 
 [*.md]
 trim_trailing_whitespace = false
+
+[Makefile]
+indent_style = tab

Makefile

@@ -0,0 +1,36 @@
+env:
+	@if [[ "$$RELEASE_NUMBER" == "" ]]; \
+		then echo "Missing environment variable: RELEASE_NUMBER."; \
+		echo 'Example: export RELEASE_NUMBER="1.0.0" (without the leading "v")'; \
+		exit 1; \
+	fi
+
+release: env
+	@echo -e "\e[1mCreating release with version number \e[36m$$RELEASE_NUMBER\e[0m"
+	@echo
+
+	sed "s/^VERSION =.*/VERSION = '$$RELEASE_NUMBER'/g" kosmorrolib/version.py > version.py
+	mv version.py kosmorrolib/version.py
+
+	pipenv run python setup.py extract_messages --output-file=kosmorrolib/locales/messages.pot > /dev/null
+
+	conventional-changelog -p angular -i CHANGELOG.md -s
+	sed "0,/\\[\\]/s/\\[\\]/[v$$RELEASE_NUMBER]/g" CHANGELOG.md > /tmp/CHANGELOG.md
+	sed -e "s/...v)/...v$$RELEASE_NUMBER)/" /tmp/CHANGELOG.md > CHANGELOG.md
+	rm /tmp/CHANGELOG.md
+
+	@echo
+	@echo -e "\e[1mRelease \e[36m$$RELEASE_NUMBER\e[39m is ready to commit."
+	@echo -e "Please review the changes, then invoke \e[33mmake finish-release\e[39m."
+
+finish-release: env
+	git add CHANGELOG.md kosmorrolib/version.py kosmorrolib/locales/messages.pot
+	git commit -m "build: bump version $$RELEASE_NUMBER"
+	git tag "v$$RELEASE_NUMBER"
+    git checkout features
+    git merge master
+    git checkout master
+
+	@echo
+	@echo -e "\e[1mVersion \e[36m$$RELEASE_NUMBER\e[39m successfully tagged!"
+	@echo -e "Invoke \e[33mgit push origin master features v$$RELEASE_NUMBER\e[39m to finish."