docs: refactor out DeveloperGuide into separate file

Do this for consistency with the other AddressBook levels.

README.adoc

@@ -1,4 +1,5 @@
 = AddressBook (Level 1)
+ifdef::env-github,env-browser[:relfileprefix: docs/]
 :toc:
 :toc-title:
 :toc-placement: preamble
@@ -18,7 +19,7 @@ running into the complications of OOP or GUI programmings.
 == User Guide
 
 This product is not meant for end-users and therefore there is no user-friendly installer.
-Please refer to the <<setting-up>> section to learn how to set up the project.
+Please refer to the <<DeveloperGuide#SettingUp, Setting up>> section to learn how to set up the project.
 
 === Starting the program
 
@@ -149,75 +150,6 @@ When running the program inside IntelliJ, there is a way to set command line par
 before running the program.
 ====
 
-'''''
-
-== Developer Guide
-
-=== Setting up
-
-*Prerequisites*
-
-* JDK 8 or later
-* IntelliJ IDE
-
-*Importing the project into IntelliJ*
-
-. Open IntelliJ (if you are not in the welcome screen, click `File` > `Close Project` to close the existing project dialog first)
-. Set up the correct JDK version
-.. Click `Configure` > `Project Defaults` > `Project Structure`
-.. If JDK 8 is listed in the drop down, select it. If it is not, click `New...` and select the directory where you installed JDK 8.
-.. Click `OK`.
-. Click `Import Project`
-. Locate the project directory and click `OK`
-. Select `Create project from existing sources` and click `Next`
-. Rename the project if you want. Click `Next`
-. Ensure that your src folder is checked. Keep clicking `Next`
-. Click `Finish`
-
-=== Design
-
-AddressBook saves data in a plain text file, one line for each person, in the format `NAME p/PHONE e/EMAIL`.
-Here is an example:
-
-....
-John Doe p/98765432 e/[email protected]
-Jane Doe p/12346758 e/[email protected]
-....
-
-All person data are loaded to memory at start up and written to the file after any command that mutates data.
-In-memory data are held in a `ArrayList<String[]>` where each `String[]` object represents a person.
-
-=== Testing
-
-*Windows*
-
-. Open a DOS window in the `test` folder
-. Run the `runtests.bat` script
-. If the script reports that there is no difference between `actual.txt` and `expected.txt`,
-the test has passed.
-
-*Mac/Unix/Linux*
-
-. Open a terminal window in the `test` folder
-. Run the `runtests.sh` script
-. If the script reports that there is no difference between `actual.txt` and `expected.txt`,
-the test has passed.
-
-*Troubleshooting test failures*
-
-* Problem: How do I examine the exact differences between `actual.txt` and `expected.txt`? +
-Solution: You can use a diff/merge tool with a GUI e.g. WinMerge (on Windows)
-
-* Problem: The two files look exactly the same, but the test script reports they are different. +
-Solution: This can happen because the line endings used by Windows is different from Unix-based
-OSes. Convert the `actual.txt` to the format used by your OS using some https://kb.iu.edu/d/acux[utility].
-
-* Problem: Test fails during the very first time. +
-Solution: The output of the very first test run could be slightly different because the program
-creates a new storage file. Tests should pass from the 2nd run onwards.
-
-'''''
-
 == Learning Outcomes
 
 _Learning Outcomes_ are the things you should be able to do after studying this code and completing the
@@ -238,7 +170,7 @@ Part B:
 * Download the source code for this project: Click on the `clone or download` link above and either,
 . download as a zip file and unzip content.
 . clone the repo (if you know how to use Git) to your Computer.
-* <<setting-up, Set up>> the project in IntelliJ.
+* <<DeveloperGuide#SettingUp, Set up>> the project in IntelliJ.
 * <<starting-the-program, Run the program>> from within IntelliJ, and try the features described in
 the <<user-guide>> section.
 
@@ -278,7 +210,7 @@ Learn https://se-edu.github.io/se-book/testing/testAutomation/testingTextUis/[ho
 
 ==== Exercise: Practice automated CLI testing
 
-* Run the tests as explained in the <<testing>> section.
+* Run the tests as explained in the <<DeveloperGuide#Testing, Testing>> section.
 * Examine the test script to understand how the script works.
 * Add a few more tests to the `input.txt`. Run the tests. It should fail.
 Modify `expected.txt` to make the tests pass again.

docs/DeveloperGuide.adoc

@@ -0,0 +1,67 @@
+= AddressBook Level 1 - Developer Guide
+:stylesDir: stylesheets
+
+[[SettingUp]]
+== Setting up
+
+*Prerequisites*
+
+* JDK 8 or later
+* IntelliJ IDE
+
+*Importing the project into IntelliJ*
+
+. Open IntelliJ (if you are not in the welcome screen, click `File` > `Close Project` to close the existing project dialog first)
+. Set up the correct JDK version
+.. Click `Configure` > `Project Defaults` > `Project Structure`
+.. If JDK 8 is listed in the drop down, select it. If it is not, click `New...` and select the directory where you installed JDK 8.
+.. Click `OK`.
+. Click `Import Project`
+. Locate the project directory and click `OK`
+. Select `Create project from existing sources` and click `Next`
+. Rename the project if you want. Click `Next`
+. Ensure that your src folder is checked. Keep clicking `Next`
+. Click `Finish`
+
+== Design
+
+AddressBook saves data in a plain text file, one line for each person, in the format `NAME p/PHONE e/EMAIL`.
+Here is an example:
+
+....
+John Doe p/98765432 e/[email protected]
+Jane Doe p/12346758 e/[email protected]
+....
+
+All person data are loaded to memory at start up and written to the file after any command that mutates data.
+In-memory data are held in a `ArrayList<String[]>` where each `String[]` object represents a person.
+
+[[Testing]]
+== Testing
+
+*Windows*
+
+. Open a DOS window in the `test` folder
+. Run the `runtests.bat` script
+. If the script reports that there is no difference between `actual.txt` and `expected.txt`,
+the test has passed.
+
+*Mac/Unix/Linux*
+
+. Open a terminal window in the `test` folder
+. Run the `runtests.sh` script
+. If the script reports that there is no difference between `actual.txt` and `expected.txt`,
+the test has passed.
+
+*Troubleshooting test failures*
+
+* Problem: How do I examine the exact differences between `actual.txt` and `expected.txt`? +
+Solution: You can use a diff/merge tool with a GUI e.g. WinMerge (on Windows)
+
+* Problem: The two files look exactly the same, but the test script reports they are different. +
+Solution: This can happen because the line endings used by Windows is different from Unix-based
+OSes. Convert the `actual.txt` to the format used by your OS using some https://kb.iu.edu/d/acux[utility].
+
+* Problem: Test fails during the very first time. +
+Solution: The output of the very first test run could be slightly different because the program
+creates a new storage file. Tests should pass from the 2nd run onwards.