title: react redux ui not re-rendering after state get updated
body: <p>I have a json array as date and I am trying to add an element in the array but my react component does not get rerendered:</p>
  
  <pre><code>export default function groupReducer(state = initialState , action){
      switch (action.type){
          case 'ADD_GROUP' :
              const newId = state.groups.length + 1;
              const newGroup = [{id : newId , name : action.text},{id : 12,name : 'myname'}];
              state.push(newGroup);
              return state
  
          default :
              return state;
      }
  }
  </code></pre>