完成saga

src/actions/header.js

@@ -3,3 +3,8 @@ import * as types from '../constants/ActionTypes'
 export const getHeader = () => ({
   type: types.HEADER_FETCH_REQUESTED
 })
+
+export const addRepo = (repo) => ({
+  type: types.ADD_REPO,
+  repo
+})

src/components/Header.js

@@ -49,7 +49,7 @@ class Header extends React.Component {
 
     return (
       <div className="text-left top-header">
-        <ModalRepoForm handleNewRepo={ this.addRepo } />
+        <ModalRepoForm handleNewRepo={ actions.addRepo } />
         <div className='col-md-10'>
           { result }
         </div>

src/constants/ActionTypes.js

@@ -7,3 +7,4 @@ export const DELETE_ELEMENT = 'DELETE_ELEMENT'
 export const HEADER_FETCH_REQUESTED = 'HEADER_FETCH_REQUESTED'
 export const HEADER_FETCH_SUCCEEDED = 'HEADER_FETCH_SUCCEEDED'
 export const HEADER_FETCH_FAILED = 'HEADER_FETCH_FAILED'
+export const ADD_REPO = 'ADD_REPO'

src/reducers/header.js

-import { HEADER_FETCH_REQUESTED, HEADER_FETCH_SUCCEEDED, HEADER_FETCH_FAILED } from '../constants/ActionTypes'
+import { HEADER_FETCH_REQUESTED, HEADER_FETCH_SUCCEEDED, HEADER_FETCH_FAILED, ADD_REPO } from '../constants/ActionTypes'
 
 const header = (state = {}, action) => {
   switch (action.type) {
@@ -18,6 +18,15 @@ const header = (state = {}, action) => {
         error_message: action.message,
         headers: []
       }
+    case ADD_REPO:
+      return {
+        isFetching: false,
+        error_message: null,
+        headers: [
+          ...state.headers,
+          action.repo
+        ]
+      }
     default:
       return state
   }