Added "required" column in table

README.md

@@ -112,18 +112,18 @@ eight_points_guzzle:
 
 ### Options
 
-| Key | Description | Example |
-| --- | --- | --- |
-| base_uri | Required value. URL of oAuth2 server.| https://example.com |
-| token_url | The path that will be concatenated with base_uri (Default: `/oauth2/token`)| /oauth/token |
-| client_id | The client identifier issued to the client during the registration process | s6BhdRkqt3 |
-| client_secret | The client secret | 7Fjfp0ZBr1KtDRbnfVdmIw |
-| username | The resource owner username | johndoe |
-| password | The resource owner password | A3ddj3w |
-| auth_location | The place where to put client_id and client_secret in auth request. Default: headers. Allowed values: body, headers. | body |
-| resource | The App ID URI of the web API (secured resource) | https://service.contoso.com/ |
-| scope | One or more scope values indicating which parts of the user's account you wish to access | administration |
-| grant_type | Grant type class path. Class should implement `Sainsburys\Guzzle\Oauth2\GrantType\GrantTypeInterface`. Default: `Sainsburys\\Guzzle\\Oauth2\\GrantType\\PasswordCredentials` | `Sainsburys\\Guzzle\\Oauth2\\GrantType\\ClientCredentials` |
+| Key | Description | Required | Example |
+| --- | --- | --- | --- |
+| base_uri | URL of oAuth2 server.| yes | https://example.com |
+| token_url | The path that will be concatenated with base_uri (Default: `/oauth2/token`)| no | /oauth/token |
+| client_id | The client identifier issued to the client during the registration process | yes | s6BhdRkqt3 |
+| client_secret | The client secret | ~ | 7Fjfp0ZBr1KtDRbnfVdmIw |
+| username | The resource owner username | for PasswordCredentials grant type | johndoe |
+| password | The resource owner password | for PasswordCredentials grant type | A3ddj3w |
+| auth_location | The place where to put client_id and client_secret in auth request. Default: headers. Allowed values: body, headers. | no | body |
+| resource | The App ID URI of the web API (secured resource) | no | https://service.contoso.com/ |
+| scope | One or more scope values indicating which parts of the user's account you wish to access | no | administration |
+| grant_type | Grant type class path. Class should implement `Sainsburys\Guzzle\Oauth2\GrantType\GrantTypeInterface`. Default: `Sainsburys\\Guzzle\\Oauth2\\GrantType\\PasswordCredentials` | no | `Sainsburys\\Guzzle\\Oauth2\\GrantType\\ClientCredentials` |
 
 See more information about middleware [here][3].