fix gyms fetching action

src\component\Card\CardContent.jsx

import React from 'react';
import { Link } from 'react-router-dom'
import {connect} from 'react-redux'
import ItemCard from './ItemCard'
import {showGyms} from '../../actions/index'

const CardContent = (props) => {
    //eliminamos el useEffect, porque ya consultamos los gyms al principio de la app

    return (
        <main class="main-content" id="Gimnasios">
            <Link to="/profile1">
                <div className="container-fluid photos">
                    <div className="row align-items-stretch">
                        {props.gyms.map((data) => {
                            return <ItemCard
                                        img={data.img}
                                        alt={data.alt}
                                        title={data.title}
                                        description={data.description}
                                        adress={data.adress}
                                        size={data.size}
                                        id={data._id}
                                    />
                        })}
                    </div>
                </div>
            </Link>
        </main>
    )
}

const mapStateToProps = state => {
    return {gyms: state.gym.gyms}
}

const GymsList = connect(mapStateToProps, {showGyms})(CardContent)

export default GymsList

src\index.js

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import * as serviceWorker from './serviceWorker';
import {Provider} from 'react-redux'
import store from './store/index'
import { showGyms } from './actions/index'

//al principio de la app consultamos los gyms
store.dispatch(showGyms())

ReactDOM.render(
  <Provider store ={store}>
    <App />
  </Provider>,
  document.getElementById('root')
);

// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: https://bit.ly/CRA-PWA
serviceWorker.unregister();

src\store\index.js

import { createStore, applyMiddleware, compose } from 'redux'
import thunk from 'redux-thunk'
import rootReducer from '../reducers/index'

//hacemos esto para poder conectar correctamente la consola de REDUX con la app y podemos ver las actions que se disparan
const composeEnhancer = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;

const store = createStore(
  rootReducer,
  composeEnhancer(applyMiddleware(thunk))
)

export default store