Add documentation

docs/src/overview.md

@@ -0,0 +1,33 @@
+# Overview
+
+Welcome! This is the documentation for [Git Repo
+Manager](https://github.com/hakoerber/git-repo-manager/) (GRM for short), a
+tool that helps you manage git repositories.
+
+GRM helps you manage git repositories in a declarative way. Configure your
+repositories in a TOML file, GRM does the rest. Take a look at [the example
+configuration](https://github.com/hakoerber/git-repo-manager/blob/master/example.config.toml)
+to get a feel for the way you configure your repositories. See the [repository
+tree chapter](./repos.md) for details.
+
+GRM also provides some tooling to work with single git repositories using
+`git-worktree`. See [the worktree chapter](./worktree.md) for more details.
+
+## Why use GRM?
+
+If you're working with a lot of git repositories, GRM can help you to manage them
+in an easy way:
+
+* You want to easily clone many repositories to a new machine.
+* You want to change remotes for multiple repositories (e.g. because your GitLab
+  domain changed).
+* You want to get an overview over all repositories you have, and check whether
+  you forgot to commit or push something.
+
+If you want to work with [git worktrees](https://git-scm.com/docs/git-worktree)
+in a streamlined, easy way, GRM provides you with an opinionated workflow. It's
+especially helpful when the following describes you:
+
+* You're juggling a lot of git branches, switching between them a lot.
+* When switching branches, you'd like to just leave your work as-is, without
+  using the stash or temporary commits.