Create docs/MAINTAINERS.md (#441)

This document will evolve as a guide for maintainers to perform all
sorts of common tasks.

Signed-off-by: Juan Cruz Viotti <jviottidc@gmail.com>

docs/MAINTAINERS.md

@@ -0,0 +1,39 @@
+Maintaining Etcher
+==================
+
+This document is meant to serve as a guide for maintainers to perform common tasks.
+
+Preparing a new version
+-----------------------
+
+- Bump the version number in the `package.json`'s `version` property.
+
+- Bump the version number in the `package.json`'s `builder.win.version` property.
+
+- Add a new entry to `CHANGELOG.md` describing what has been added, changed, or removed. Please use the imperative mode and capitalize the first letter of each item.
+
+- Link the `CHANGELOG.md` entry to the GitHub page displaying the diffs between the previous and the current version.
+
+```markdown
+https://github.com/resin-io/etcher/compare/<previous>...<current>
+```
+
+- Re-take `screenshot.png` so it displays the latest version in the bottom right corner.
+- Commit the changes with the version number as the commit title, including the `v` prefix, to `master`. For example:
+
+```sh
+git commit -m "v1.0.0" # not 1.0.0
+```
+
+- Create an annotated tag for the new version. The commit title should equal the annotated tag name. For example:
+
+```sh
+git tag -a v1.0.0 -m "v1.0.0"
+```
+
+- Push the commit and the annotated tag.
+
+```sh
+git push
+git push --tags
+```