📝 Add doc about asset proposals (zenika-open-source#27)

Author: bpetetot

README.md

@@ -10,6 +10,8 @@ Play on **[https://pimpmyduck.zenika.com](https://pimpmyduck.zenika.com)**.
 
 Contributions, issues and feature requests are welcome! Feel free to check [issues page](https://github.com/zenika-open-source/my-zenikanard/issues).
 
+See the [Asset proposal documentation](./proposals/README.md), if you want to add a new asset to Pimp My Duck.
+
 All development instructions are explained in the [contributing guide](./.github/CONTRIBUTING.md).
 
 ## License

proposals/README.md

@@ -0,0 +1,22 @@
+# How to propose an asset to "Pimp My Duck" ?
+
+To propose a new asset you have to create a PR with :
+- The asset as SVG file into the `/proposals` folder
+- Give the asset name and category into the PR description
+
+Here is the category list:
+- Eyes
+- Glasses
+- Hair
+- Hats
+- Mouth
+- Faces
+- Wears
+- Body tatoo
+- Accessories
+
+The asset can be built using the [Zenikanard template](./zenikanard_template.svg) SVG file as reference.
+
+The final asset SVG file must NOT contain the Zenikanard, it's just a template to help the design.
+
+After the PR, reviewed and merged. A maintainer will integrate it into "Pimp My Duck".