Added customization documentation

readme.md

@@ -44,3 +44,28 @@ In the root directory of the repository run:
 ```
 python server/main.py
 ```
+
+## Customizing
+
+A way to change the equation may be implemented in the future, but currently it
+is hard coded.
+
+You can change the function `YTDServerFactory.func(x: int, y: int, z: int)` in
+`server/main.py` to implement your own equation. This function accepts the world
+coordinates and returns a dictionary representing the block at that location.
+
+Here are examples of block representations accepted by quarry. These definitions
+are from the top of `server/main.py`.
+
+```
+BLOCK_EMPTY = {'name': 'minecraft:air'}
+BLOCK_SURFACE = {'name': 'minecraft:grass_block', 'snowy': 'false'}
+BLOCK_SUBSURFACE = {'name': 'minecraft:dirt'}
+BLOCK_UNDERGROUND = {'name': 'minecraft:stone'}
+BLOCK_DEFAULT = {'name': 'minecraft:cobblestone'}
+```
+
+Information about blocks and block states can be found in
+`generate_data\generated\reports\blocks.json` if the data generator has been
+ran. You can also find this information online from the
+[Minecraft Wiki](https://minecraft.wiki/).