Enable user to show or hide defalut Twitter icon in button and update documentation

Author: ivanvs

README.md

@@ -37,12 +37,20 @@
 | className       |string  |                     |class name for component                                                       |
 | dialogWidth     |number  |600                  |dialog width                                                                   |
 | dialogHeight    |number  |400                  |dialog height                                                                  |
-
+| showIcon        |bool    |true                 |should default icon be visible                                                 |
 
 # Examples
 
 Full example can be found in [example](https://github.com/GenFirst/react-twitter-login/tree/master/example) folder.
 
+You can find tutorial that explains in details how to implement Twitter authentication with RESTful backend [here](https://medium.com/@robince885/how-to-do-twitter-authentication-with-react-and-restful-api-e525f30c62bb).
+
+# Workflow
+
+The detailed explanation of the whole process can be found in Twitter documentation. In picture below you can find out all the steps that are needed.
+
+![Twitter authentication workflow](https://cdn-images-1.medium.com/max/800/1*RTsSRbVeEzPaC68hRT8n2g.png)
+
 # License
 
 react-twitter-auth is released under [MIT License](https://opensource.org/licenses/MIT).

example/twitter-example/src/App.js

@@ -23,7 +23,11 @@ class App extends Component {
   render() {
     return (
       <div>
-        <TwitterLogin loginUrl="http://localhost:4000/api/v1/auth/twitter" onFailure={this.onFailed} onSuccess={this.onSuccess} requestTokenUrl="http://localhost:4000/api/v1/auth/twitter/reverse"/>
+        <TwitterLogin loginUrl="http://localhost:4000/api/v1/auth/twitter"
+                      onFailure={this.onFailed}
+                      onSuccess={this.onSuccess}
+                      requestTokenUrl="http://localhost:4000/api/v1/auth/twitter/reverse"
+                      showIcon={true}/>
       </div>
     );
   }

src/index.js

@@ -97,9 +97,11 @@ class TwitterLogin extends Component {
   }
 
   getDefaultButtonContent() {
+    const defaultIcon = this.props.showIcon? <TwitterIcon color='#00aced' size={25}/> : null;
+
     return (
       <span>
-        <TwitterIcon color='#00aced' size={25}/> {this.props.text}
+        {defaultIcon} {this.props.text}
       </span>
     );
   }
@@ -128,15 +130,17 @@ TwitterLogin.propTypes = {
   style: PropTypes.object,
   className: PropTypes.string,
   dialogWidth: PropTypes.number,
-  dialogHeight: PropTypes.number
+  dialogHeight: PropTypes.number,
+  showIcon: PropTypes.bool
 };
 
 TwitterLogin.defaultProps = {
   tag: 'button',
   text: 'Sign in with Twitter',
   disabled: false,
   dialogWidth: 600,
-  dialogHeight: 400
+  dialogHeight: 400,
+  showIcon: true
 };
 
 export default TwitterLogin;