Sending POST request rails

I'm new in Ruby/Rails and I am trying to create simple API that will hold beer model (name and alcohol percent). I implemented API with rails gem rails-api but I have problem with sending POST request. I'm getting 400 ERROR due to bad syntax (using postman for sending requests).

I dont know what I am doing wrong. Here's my beers controller:

class BeersController < ApplicationController  before_action :set_beer, only: [:show, :update, :destroy]  # GET /beers  # GET /beers.json  def index    @beers = Beer.all    render json: @beers  end  # GET /beers/1  # GET /beers/1.json  def show    render json: @beer  end  # POST /beers  # POST /beers.json  def create    @beer = Beer.new(beer_params)    if @beer.save      render json: @beer, status: :created, location: @beer    else      render json: @beer.errors, status: :unprocessable_entity    end  end  # PATCH/PUT /beers/1  # PATCH/PUT /beers/1.json  def update    @beer = Beer.find(params[:id])    if @beer.update(beer_params)      head :no_content    else      render json: @beer.errors, status: :unprocessable_entity    end  end  # DELETE /beers/1  # DELETE /beers/1.json  def destroy    @beer.destroy    head :no_content  end  private    def set_beer      @beer = Beer.find(params[:id])    end    def beer_params      params.require(:beer).permit(:name, :percent)    endend

Hope you can help me solve this problem.

When I print logs after this request I get this from Heroku logs:

2015-04-06T11:51:40.715123+00:00 heroku[router]: at=info method=POST path="/beer s" host=drinkapptest.herokuapp.com request_id=e4557a13-1391-4e30-ab8a-069e714b93 d0 fwd="89.164.165.138" dyno=web.1 connect=0ms service=9ms status=400 bytes=264