Add initial episode content

episodes/08-conflicts.md

@@ -7,9 +7,21 @@ SPDX-License-Identifier: CC-BY-4.0
 # Conflicts
 
 In this episode, we create [a conflict](https://swcarpentry.github.io/git-novice/fig/conflict.svg) and resolve it.
+In addition, we briefly introduce the typically used concepts of `branching` and `merging`.
 Please see [the original Conflict episode](https://swcarpentry.github.io/git-novice/09-conflict/index.html) for further details.
-In addition, [conflicts.pptx](extras/conflicts.pptx) shows an animation of all performed
-steps.
+In addition, [conflicts.pptx](extras/conflicts.pptx) shows an animation of all performed steps.
+
+## Background
+
+- `Branching` is an important concept in Git.
+  - A `branch` is a specific series of commits of the repository.
+  - The `master` branch reflects the current state / "truth" of the repository and typically acts as synchronization point for starting off new work and re-integrating finished work.
+  - Every Git repository can contain as many branches as you want.
+  - Every Git repository can have different branches.
+  - Branches can be shared between Git repositories.
+- Typically, you start a new piece of work by creating a new `branch` out of the `master` branch.
+- Once, you are finished with your work you re-integrate it by `merging` your working branch back into the `master` branch.
+- When re-integrating your work, it might happen that `conflicts` occur because someone else changed the same lines as you.
 
 ## Configure some Useful Details
 
@@ -18,28 +30,66 @@ steps.
   - View diff while writing commit message `git config --global commit.verbose true`
   - Test with `git config --global --edit`
 
-## Create a Conflict
+## Create a new Branch and start your Work
+
+- Show the existing branches
+  - `git branch --all`
+  - Explain the labels `master` and `HEAD`
+  - Explain remote and local branches
+- Show graph of the repository
+  - Draw state of the repository
+  - Verify with `git graph`
+
+```
+o - o <- HEAD, master
+```
+
+- Create a new branches
+  - `git branch mumy-info`
+- Show what changed
+  - Verify with `git branch` and `git graph`
+  - Explain that `*` marks where the HEAD is pointing to
+
+```
+o - o <- HEAD, master, mummy-info
+```
+
+- Switch to the newly created branch
+  - `git checkout mummy-info` (Git version >= 2.23 supports: `git switch <BRANCH NAME>`)
+  - Verify with `git graph`
+- Edit the file `mars.txt` and commit the changes
+  - Add a new sentence at the end of the file: `Mummy will appreciate sand storms on Mars`
+  - Add & commit it: `git add mars.txt`, `git commit -m "Add advantages for the Mummy"`
+  - Verify with `git branch` and `git graph`
+
+```
+      o <- HEAD, mummy-info
+     /
+o - o   <- master
+```
+
+## Prepare the Conflict
+
+- Switch back to the `master` branch
+  - `git checkout master` (Git version >= 2.23 supports: `git switch <BRANCH NAME>`)
+  - Verify with `git graph`
+- Edit the file `mars.txt` and commit the changes
+  - Add a new sentence at the end of the file: `Generating solar energy is less effective on Mars`
+  - Add & commit it: `git add mars.txt`, `git commit -m "Add information about energy generation"`
+  - Verify with `git branch` and `git graph`
+
+```
+      o   <- mummy-info
+     /
+o - o - o <- HEAD, master
+```
 
-- In the remote repository: 
-  - Change the sentence on first line to `Cold, dry and rocky, but everything is my favorite color` in `mars.txt`
-  - Add a new sentence: `Mummy will appreciate sand storms on Mars` to `mars.txt`
-  - Commit the changes with the commit message `"Prepare merge conflict on GitLab"`
-  - Show GitLab's `/commits` or `/graph` pages
-- In the local repository:
-  - Add a new sentence: `Generating solar energy is less effective on Mars` to `mars.txt`
-  - Add & commit it: `git add mars.txt` & `git commit -m "Prepare merge conflict locally"`
-- Show local commit log:
-  - `git graph`
-- Show that a push to remote fails:
-  - `git push origin master`
-  - Explain reasons
-  - Optional: `git fetch -v` 
- 
 ## Resolve the Conflict
 
-- Pull from remote repository:
-  - `git pull`
-- Perform manual merge with the editor by editing the `<<< ... === ... >>>` section and removal of these conflict markers
+- Merge the working branch (`mummy-info`) into the `master`branch
+  - `git merge mummy-info`
+  - Explain the output and the consequences
+- Resolve the conflict manually with the help of the editor by editing the `<<< ... === ... >>>` section and removing the conflict markers
 - Mark the conflict as resolved:
   - `git add mars.txt`
   - `git commit` (without commit message => explain interactive commit with default message) 
@@ -47,12 +97,12 @@ steps.
   - `git graph`
   - Highlight the split with coexisting commits
   - Highlight that no version/commit is lost in a merge
-  - Highlight that `origin/master` is behind `master` (local Git repository)  
-- Push result to remote repository:
-  - `git push`
-- Show local commit log:
-  - `git graph`
-  - Highlight that `origin/master` and  `master` (local Git repository) are equal
+
+```
+        o     <- mummy-info
+      /   \
+o - o - o - o <- HEAD, master
+```
 
 ## Key Points