Move content from CONTRIBUTING.md and split existing content

source/developers/development_catching_up.markdown

@@ -0,0 +1,35 @@
+---
+layout: page
+title: "Catching up with Reality"
+description: "Update your fork with the latest commit."
+date: 2016-07-01 20:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+---
+
+If you're taking a while developing your feature and would like to catch up with what's in the current Home Assistant `dev` branch, you can use `git rebase` to do so. This will pull the latest Home Assistant changes locally, rewind your commits, bring in the latest changes from Home Assistant and then replay all of your commits on top.
+
+```bash
+# Run this from your feature branch
+$ git fetch upstream dev  # to pull the latest changes into a local dev branch
+$ git rebase upstream/dev # to put those changes into your feature branch before your changes
+```
+
+If rebase detects conflicts, you can repeat the following process until all changes have been resolved:
+
+1. `git status` will show you the file with the conflict.
+2. Edit the file and resolving the lines between `<<<< | >>>>`
+3. Add the modified file `git add <file>` or `git add .`
+4. Continue rebase `git rebase --continue`
+5. Repeat until you've resolved all conflicts.
+
+There is other workflows that is covered in detail in the [Github documentation](https://help.github.com/articles/fork-a-repo/). Add an additional `remote` after you clone your fork.
+
+```bash
+$ git remote add upstream https://github.com/home-assistant/home-assistant.git
+```
+
+and then simply `git pull --rebase upstream dev`.
+