def create
      @post = Post.new(params.permit(:title, :content, :board_id))
      @post.user = @user
      if (@post.save)
        render json: @post, status: :created
      else
        render json: @post.errors, status: 422
      end
    end
def create
      @post = Post.new(params.permit(:title, :content, :board_id))
      @post.user = @user
      if (@post.save)
        render json: @post, status: :created
      else
        render json: @post.errors, status: 422
      end
    end
Creates a single post belonging to the board

 `POST /api/boards/:board_id/posts/`