implemented post creation, deletion and update api

backend/models/post.go

@@ -6,5 +6,5 @@ type Post struct {
 	gorm.Model        // includes ID, CreatedAt, UpdatedAt, DeletedAt
 	Title      string `gorm:"not null"`
 	Content    string `gorm:"type:text; not null"`
-	AuthorID   uint   // foreign key to User
+	Author     string `gorm:"not null"`
 }