diff --git a/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Comment.kt b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Comment.kt
new file mode 100644
index 00000000..3d93a674
--- /dev/null
+++ b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Comment.kt
@@ -0,0 +1,28 @@
+package com.gamelounge.backend.entity
+import jakarta.persistence.*
+import java.time.Instant
+
+@Entity
+@Table(name = "comments")
+class Comment(
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    val commentId: Long? = null,
+
+    val content: String = "",
+    val creationDate: Instant = Instant.now(),
+    val upvotes: Int = 0,
+    val downvotes: Int = 0,
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "postId")
+    val post: Post? = null,
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "lfgId")
+    val lfg: LFG? = null,
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "userId")
+    val user: User? = null
+)
\ No newline at end of file
diff --git a/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Game.kt b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Game.kt
new file mode 100644
index 00000000..82a6776d
--- /dev/null
+++ b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Game.kt
@@ -0,0 +1,32 @@
+package com.gamelounge.backend.entity
+
+import jakarta.persistence.GeneratedValue
+import jakarta.persistence.GenerationType
+import jakarta.persistence.Id
+import jakarta.persistence.ManyToOne
+
+import jakarta.persistence.*
+
+@Entity
+@Table(name = "games")
+class Game (
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    val gameId: Long? = null,
+
+    val title: String = "",
+    val description: String = "",
+    val genre: String = "",
+    val platform: String = "",
+    val avatarDetails: String = "", // Consider a more complex structure
+    val playerNumber: String = "",
+    val releaseYear: Int = 0,
+    val universe: String = "",
+    val mechanics: String = "",
+    val playtime: String = "",
+    val mapInformation: String = "",
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "userId")
+    val user: User? = null
+)
\ No newline at end of file
diff --git a/app/backend/src/main/kotlin/com/gamelounge/backend/entity/LFG.kt b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/LFG.kt
new file mode 100644
index 00000000..34fdd0d2
--- /dev/null
+++ b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/LFG.kt
@@ -0,0 +1,28 @@
+package com.gamelounge.backend.entity
+
+import jakarta.persistence.*
+import java.time.Instant
+
+@Entity
+@Table(name = "lfg")
+class LFG(
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    val lfgId: Long? = null,
+
+    val title: String = "",
+    val description: String = "",
+    val requiredPlatform: String = "",
+    val requiredLanguage: String = "",
+    val micCamRequirement: Boolean = true,
+    val memberCapacity: Int = 0,
+    val creationDate: Instant = Instant.now(),
+    val tags: String? = "",
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "userId")
+    val user: User? = null,
+
+    @OneToMany(mappedBy = "lfg", cascade = arrayOf(CascadeType.ALL), orphanRemoval = true)
+    val comments: List<Comment> = mutableListOf()
+)
\ No newline at end of file
diff --git a/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Post.kt b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Post.kt
new file mode 100644
index 00000000..641c78d6
--- /dev/null
+++ b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Post.kt
@@ -0,0 +1,28 @@
+package com.gamelounge.backend.entity
+import jakarta.persistence.*
+import lombok.NoArgsConstructor
+import java.time.Instant
+
+@Entity
+@Table(name = "posts")
+class Post(
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    val postId: Long? = null,
+
+    val content: String = "",
+    val creationDate: Instant = Instant.now(),
+    val upvotes: Int = 0,
+    val downvotes: Int = 0,
+    val tags: String? = "",
+    val category: String = "",
+    val relatedGamePage: String? = "",
+    val annotations: String? = "",
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "userId")
+    val user: User? = null,
+
+    @OneToMany(mappedBy = "post", cascade = arrayOf(CascadeType.ALL), orphanRemoval = true)
+    val comments: List<Comment> = mutableListOf()
+)
\ No newline at end of file
diff --git a/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Tag.kt b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Tag.kt
new file mode 100644
index 00000000..c202f64e
--- /dev/null
+++ b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/Tag.kt
@@ -0,0 +1,19 @@
+package com.gamelounge.backend.entity
+
+import jakarta.persistence.*
+
+@Entity
+@Table(name = "tags")
+class Tag(
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    val tagId: Long = 0,
+
+    val name: String = "",
+
+    @ManyToMany(mappedBy = "tags")
+    val posts: List<Post> = mutableListOf(),
+
+    @ManyToMany(mappedBy = "tags")
+    val lfgs: List<LFG> = mutableListOf()
+)
\ No newline at end of file
diff --git a/app/backend/src/main/kotlin/com/gamelounge/backend/entity/User.kt b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/User.kt
index b2fabafc..4f3b700f 100644
--- a/app/backend/src/main/kotlin/com/gamelounge/backend/entity/User.kt
+++ b/app/backend/src/main/kotlin/com/gamelounge/backend/entity/User.kt
@@ -1,21 +1,34 @@
 package com.gamelounge.backend.entity
 
-
-import jakarta.persistence.Entity
-import jakarta.persistence.Id
-import jakarta.persistence.Table
+import jakarta.persistence.*
+import lombok.Data
+import lombok.NoArgsConstructor
 
 @Entity
-@Table(name ="users")
+@Data
+@NoArgsConstructor
 class User(
-        @Id val username: String,
-        val email: String,
-        val name: String,
-        val surname: String,
-        val image: ByteArray? = null,
-        var passwordHash: ByteArray,
-        var salt: ByteArray,
-    ){
-    constructor() : this("", "", "", "", null, ByteArray(0), ByteArray(0))
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    val userId: Long = 0,
+
+    val username: String = "",
+    val email: String = "",
+    val password: String = "",
+    val profilePicture: String? = null,
+    val about: String? = null,
+    var passwordHash: ByteArray = ByteArray(0),
+    var salt: ByteArray = ByteArray(0),
+
+    @OneToMany(mappedBy = "user", cascade = [CascadeType.ALL], orphanRemoval = true)
+    val posts: List<Post>? = mutableListOf(),
+
+    @OneToMany(mappedBy = "user", cascade = [CascadeType.ALL], orphanRemoval = true)
+    val games: List<Game>? = mutableListOf(),
+
+    @OneToMany(mappedBy = "user", cascade = [CascadeType.ALL], orphanRemoval = true)
+    val LFGs: List<LFG>? = mutableListOf(),
 
-}
\ No newline at end of file
+    @ManyToMany(mappedBy = "user", cascade = [CascadeType.ALL])
+    val tags: List<Tag>? = mutableListOf()
+)
\ No newline at end of file
diff --git a/app/backend/src/main/kotlin/com/gamelounge/backend/model/RegisterationRequest.kt b/app/backend/src/main/kotlin/com/gamelounge/backend/model/RegisterationRequest.kt
index 9900e403..cf12e47a 100644
--- a/app/backend/src/main/kotlin/com/gamelounge/backend/model/RegisterationRequest.kt
+++ b/app/backend/src/main/kotlin/com/gamelounge/backend/model/RegisterationRequest.kt
@@ -2,6 +2,7 @@ package com.gamelounge.backend.model
 
 
 import com.fasterxml.jackson.annotation.JsonProperty
+import java.net.URL
 
 data class RegisterationRequest (
     @JsonProperty("username")
@@ -13,12 +14,6 @@ data class RegisterationRequest (
     @JsonProperty("email")
     val email: String,
 
-    @JsonProperty("name")
-    val name: String,
-
-    @JsonProperty("surname")
-    val surname: String,
-
     @JsonProperty("image")
     val image: ByteArray?
 
diff --git a/app/backend/src/main/kotlin/com/gamelounge/backend/service/AccessService.kt b/app/backend/src/main/kotlin/com/gamelounge/backend/service/AccessService.kt
index ab6664c6..d1b19f0c 100644
--- a/app/backend/src/main/kotlin/com/gamelounge/backend/service/AccessService.kt
+++ b/app/backend/src/main/kotlin/com/gamelounge/backend/service/AccessService.kt
@@ -33,7 +33,10 @@ class AccessService(
         if (userRepository.existsByUsername(request.username)){
             throw UsernameAlreadyExistException("The username already exists!")
         }
-        userRepository.save(User(request.username, request.email, request.name, request.surname, request.image, passwordHash, salt))
+//        val imageUrl: String = s3Service.save(request.image)
+        val imageUrl: String = "some-url"
+        userRepository.save(User(username = request.username, email = request.email, password = request.password, profilePicture = imageUrl))
+
     }
 
     fun login(username: String, password: String): UUID {
diff --git a/app/backend/src/main/resources/application.properties b/app/backend/src/main/resources/application.properties
index 4d70e4d6..db855796 100644
--- a/app/backend/src/main/resources/application.properties
+++ b/app/backend/src/main/resources/application.properties
@@ -1,7 +1,11 @@
 # Database properties
-spring.datasource.url=${SPRING_DATASOURCE_URL}
-spring.datasource.username=${SPRING_DATASOURCE_USERNAME}
-spring.datasource.password=${SPRING_DATASOURCE_PASSWORD}
+#spring.datasource.url=${SPRING_DATASOURCE_URL}
+#spring.datasource.username=${SPRING_DATASOURCE_USERNAME}
+#spring.datasource.password=${SPRING_DATASOURCE_PASSWORD}
+
+spring.datasource.url=jdbc:postgresql://localhost:5433/postgres
+spring.datasource.username=postgres
+spring.datasource.password=000000
 
 # Hibernate properties
 spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect