fix(playground): resources are relative

Author: NaejDoree

playground/getting-started/tutorial-1-introduction.md

@@ -14,7 +14,7 @@ The `Referee` class must implement the methods `init` and `gameTurn`. The `Playe
 
 The entry point of the game is the class `SoloGameManager` or `MultiplayerGameManager` (corresponding to the type of game you are creating). This class calls the `Referee` on each turn, and sends data to the viewer.
 
-![Main classes](playground/resources/schema-sdk.svg)
+![Main classes](resources/schema-sdk.svg)
 
 # Resources
 

playground/getting-started/tutorial-2-multiplayer.md

@@ -67,7 +67,7 @@ The class to run is test/java/Main.java:
 
 This will launch a [web server](http://localhost:8888/) to serve a page with the viewer of the game.
 
-![Game Preview](playground/resources/testhtml.png)
+![Game Preview](resources/testhtml.png)
 
 Use this page to see the rendering of your game. It also allows you to export a zip archive of the game.
 

playground/getting-started/tutorial-3-solo.md

@@ -74,7 +74,7 @@ Here's the file hierarchy for the project Fishy Adventures:
 
 The class to run is test/java/Main.java. This will launch a [web server](http://localhost:8888/) to serve a page with the viewer of the game.
 
-![Game Preview](playground/resources/testhtml.png)
+![Game Preview](resources/testhtml.png)
 
 Use this page to see the rendering of your game. It also allows you to export a zip archive of the game.
 

playground/getting-started/tutorial-4-opti.md

@@ -10,7 +10,7 @@ As a Solo game, an Optimization game has test cases. Their purpose here is diffe
 
 Let's take the example of Fishy Adventures:
 
-![Game preview](playground/resources/optiviewer.png)
+![Game preview](resources/optiviewer.png)
 
 In the Solo version of this game, the purpose is to collect one egg. Here, there are several groups of eggs with values (the number of eggs in the group) and you cannot gather all of them. You will need to *optimize* the path you take to collect as many eggs as possible. See the [Optimization games features](playground/core-concepts/core-3-game-manager.md#optimization-game-features) for more details.
 

playground/graphics/graphics-4-spritesheets.md

@@ -8,7 +8,7 @@ This is the easiest way to create a set of sprites from a spritesheet. This solu
 
 For this example, we will use this spritesheet (taken from our [free to use assets repository](https://github.com/CodinGame/codingame-sdk-assets)):
 
-![Spritesheet](playground/resources/spritesheet.png)
+![Spritesheet](resources/spritesheet.png)
 
 - 12 images
 - 4 images per row

playground/graphics/graphics-6-advanced.md

@@ -16,7 +16,7 @@ The behaviour can be different:
 
 If your game uses tiles, you might experience some artifacts when resizing the viewer.
 
-![Artifacts](playground/resources/artifacts.png)
+![Artifacts](resources/artifacts.png)
 
 They appear due to rounding errors. These artifacts can be reduced thanks to `BufferedGroup`. Buffered groups work the same way as `Group`, but the viewer renders its children when they change into a dynamic texture before being displayed. 
 ⚠**Warnings**⚠