Add dev git env section

guides/contributing.rst

@@ -320,6 +320,63 @@ Finally, for documentation changes go to your esphome-docs folder, and install s
 Or alternatively just submit a draft PR to the docs repo and wait for netlify to create
 a build preview.
 
+Setting Up Git Environment
+--------------------------
+
+ESPHome's code-base is hosted on GitHub, and contributing is done exclusively through
+"Pull Requests" (PRs) in the GitHub interface. So you need to set up your git environment
+first.
+
+When you want to create a patch for ESPHome, first go to the repository you want to contribute to
+(esphome, esphome-core, etc) and click fork in the top right corner. This will create
+a fork of the repository that you can modify and create git branches on.
+
+.. code-block:: bash
+
+    # Clone your fork
+    git clone https://github.com/<YOUR_GITHUB_USERNAME>/<REPO_NAME>.git
+    # For example: git clone https://github.com/OttoWinter/esphome-core.git
+
+    # Add "upstream" remote
+    git remote add upstream https://github.com/esphome/<REPO_NAME>.git
+    # For example: git clone https://github.com/esphome/esphome-core.git
+
+    # For each patch, create a new branch from latest dev
+    git checkout dev
+    git pull upstream dev
+    git checkout -b <MY_NEW_FEATURE>
+    # For example: git checkout -b gpio-switch-fix
+
+    # Make your modifications, then commit changes with message describing changes
+    git add .
+    git commit -m "<COMMIT_MESSAGE>"
+    # For example: git commit -m "Fix GPIO Switch Not Turning Off Interlocked Switches"
+
+    # Upload changes
+    git push -u origin <BRANCH_NAME>
+    # For example: git push -u origin gpio-switch-fix
+
+Then go to your repository fork in GitHub and wait for a create pull request message to show
+up in the top (alternatively go to branches and create it from there). Fill out the
+Pull Request template outlining your changes; if your PR is not ready to merge yet please
+mark it as a draft PR in the dropdown of the green "create PR" button.
+
+**Review Process:** ESPHome's code base tries to have a high code standard. At the bottom
+of the Pull Request you will be able to see the "Travis" continuous integration check which
+will automatically go through your patch and try to spot errors. If the CI check fails,
+please see the travis log and fix all errors that appear there. Only PRs that pass the automated
+checks can be merged!
+
+**Catching up with reality**: Sometimes other commits have been made to the same files
+you edited. Then your changes need to be re-applied on top of the latest changes with
+a "rebase". More info `here <https://developers.home-assistant.io/docs/en/development_catching_up.html>`__.
+
+.. code-block:: bash
+
+    # Fetch the latest upstream changes and apply them
+    git fetch upstream dev
+    git rebase upstream/dev
+
 Contributing to ESPHome-Core
 ----------------------------
 

guides/faq.rst

@@ -159,8 +159,19 @@ To install the dev version of ESPHome:
 - In Hass.io: In the ESPHome add-on repository there's also a second add-on called ``ESPHome Dev``.
   Install that and stop the stable version (both can't run at the same time without port collisions).
 - From ``pip``: Run ``pip install https://github.com/esphome/esphome/archive/dev.zip``
-- From docker: Run ``docker pull esphome/esphome:dev`` and use ``esphome/esphome:dev`` in all
-  commands.
+- From docker, you need to build the docker image yourself (automated dev builds are not possible
+  due to docker hubs limited build quota)
+
+  .. code-block:: bash
+
+      git clone https://github.com/esphome/esphome.git
+      cd esphome
+      docker build -t esphome-dev -f docker/Dockerfile .
+      docker run [...] -it esphome-dev livingroom.yaml compile
+
+      # Update image and rebuild
+      git pull
+      docker build -t esphome-dev -f docker/Dockerfile .
 
 The latest dev docs are here: `next.esphome.io <https://next.esphome.io/>`__
 
@@ -181,7 +192,7 @@ Sure! I'd be happy to help :) You can contact me here:
 -  ESPHome `issue <https://github.com/esphome/issues>`__ and
    `feature request <https://github.com/esphome/feature-requests>`__ issue trackers. Preferably only for issues and
    feature requests.
--  Alternatively, also under contact (at) esphome.io
+-  Alternatively, also under contact (at) esphome.io (NO SUPPORT!)
 
 .. _wifi-problems: