diff --git a/README.md b/README.md
index c5eb299..deb2939 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,19 @@
 # PoKeMoNg
 
+  * [About](#about)
+    + [🗂️ DCM](#-dcm)
+    + [🧬 UML Class diagram](#-uml-class-diagram)
+    + [🗺 NoSQL Schema Versioning Strategy](#-nosql-schema-versioning-strategy)
+      - [Schema Versioning Pattern](#schema-versioning-pattern)
+      - [Incremental Document Migration](#incremental-document-migration)
+  * [Prep steps](#prep-steps)
+    + [♨️ Java version](#-java-version)
+    + [🔐 Database connection](#-database-connection)
+  * [Running the application in dev mode](#running-the-application-in-dev-mode)
+    + [🏴‍☠️ SwaggerUI](#-swaggerui)
+    + [🩺 API testing tools](#-api-testing-tools)
+    + [📱 Front end (later)](#-front-end-later)
+
 This is a [Quarkus](https://quarkus.io/) / [MongoDB](https://mongodb.com/) app for educational purposes.
 
 Instructions are [here](https://clientserveur-courses.clubinfo-clermont.fr/Notation.html) for reference.
@@ -20,9 +34,76 @@ CRUD operations on `Pokemongs`, `Trainers`, `Moves`, and `Types`.
 
 ### 🧬 UML Class diagram
 
-<img src="./docs/nosql_uml.png" alt="UML Class Diagram" title="UML Class Diagram">
+```mermaid
+classDiagram
+
+class Trainer {
+  + id: ObjectId
+  + name: string
+  + dob: date
+  + wins: int
+  + losses: int
+}
+
+class Pokemong {
+  + id: ObjectId
+  + nickname: string?
+  + dob: date
+  + level: int
+  + pokedexId: int
+  + evoStage: int
+  + evoTrack: PokemongName[]
+}
+
+class Move {
+  + id: ObjectId
+  + name: string
+  + category: MoveCategoryName
+  + power: int
+  + accuracy: int
+}
+
+class Type {
+  + id: ObjectId
+  + name: TypeName
+  + weakAgainst: TypeName[]
+  + effectiveAgainst: TypeName[]
+}
+
+class TypeName {
+    <<enumeration>>
+  + FIRE
+  + WATER
+  + ...
+}
+
+class PokemongName {
+    <<enumeration>>
+  + BULBASAUR
+  + IVYSAUR
+  + ...
+}
+
+class MoveCategoryName {
+    <<enumeration>>
+  + PHYSICAL
+  + SPECIAL
+  + STATUS
+}
+
+Trainer --> "0..*" Trainer: pastOpponents
+Trainer --> "0..*" Pokemong: pokemongs
+Pokemong --> "0..1" Trainer: trainer
+Pokemong --> "0..4" Move: moveSet
+Pokemong --> "1..2" Type: types
+Move --> Type: type
+
+Type ..> TypeName
+Pokemong ..> PokemongName
+Move ..> MoveCategoryName
+```
 
-### NoSQL Schema Versioning Strategy
+### 🗺 NoSQL Schema Versioning Strategy
 
 This application uses MongoDB, a NoSQL database, which provides flexibility in our data model. While this flexibility
 has
diff --git a/docs/DB.md b/docs/DB.md
index f7dfcb2..6ced79a 100644
--- a/docs/DB.md
+++ b/docs/DB.md
@@ -64,7 +64,7 @@
         * => referencing
     - [x] pokemongs.types: one-to-few [1;2]
         * => embedding
-    - [x] pokemongs.moveSet: one-to-few [1;4] but will also need to be queried independently
+    - [x] pokemongs.moveSet: one-to-few [0;4] but will also need to be queried independently
         * => referencing + denormalizing on  "name"
 - Move
     - [x] moves.type: one-to-one [1;1]
diff --git a/docs/mcd.png b/docs/mcd.png
index 20e3532..5c35faf 100644
Binary files a/docs/mcd.png and b/docs/mcd.png differ
diff --git a/src/main/java/fr/uca/iut/services/PokemongService.java b/src/main/java/fr/uca/iut/services/PokemongService.java
index a3c0743..085d300 100644
--- a/src/main/java/fr/uca/iut/services/PokemongService.java
+++ b/src/main/java/fr/uca/iut/services/PokemongService.java
@@ -93,8 +93,8 @@ public class PokemongService extends GenericService<Pokemong> {
         if (moveSet == null) {
             errors.add("pokemong move set was null");
         } else {
-            if (moveSet.size() == 0 || moveSet.size() > 4) {
-                errors.add("pokemong move set was empty or had more than 4 moves");
+            if (moveSet.size() > 4) {
+                errors.add("pokemong move set had more than 4 moves");
             }
             for (PokemongMove move : moveSet) {
                 String moveId = move.getId();
diff --git a/src/main/resources/META-INF/openapi.yaml b/src/main/resources/META-INF/openapi.yaml
index ab5d825..ba0cc4b 100644
--- a/src/main/resources/META-INF/openapi.yaml
+++ b/src/main/resources/META-INF/openapi.yaml
@@ -344,7 +344,6 @@ components:
             $ref: '#/components/schemas/Type'
         moveSet:
           type: array
-          minItems: 1
           maxItems: 4
           items:
             $ref: '#/components/schemas/PokemongMove'