fix: make selecting at least one contribution type mandatory (#56)

* Add @machour as a contributor

* fix: make selecting at least one contribution type mandatory

.all-contributorsrc

@@ -89,6 +89,15 @@
       "contributions": [
         "tool"
       ]
+    },
+    {
+      "login": "machour",
+      "name": "Mehdi Achour",
+      "avatar_url": "https://avatars2.githubusercontent.com/u/304450?v=4",
+      "profile": "https://machour.idk.tn/",
+      "contributions": [
+        "code"
+      ]
     }
   ]
 }

README.md

@@ -1,7 +1,7 @@
 # all-contributors-cli
 
 [![version](https://img.shields.io/npm/v/all-contributors-cli.svg)](http://npm.im/all-contributors-cli)
-[![All Contributors](https://img.shields.io/badge/all_contributors-9-orange.svg?style=flat-square)](#contributors)
+[![All Contributors](https://img.shields.io/badge/all_contributors-10-orange.svg?style=flat-square)](#contributors)
 
 This is a tool to help automate adding contributor acknowledgements according to the [all-contributors](https://github.com/kentcdodds/all-contributors) specification.
 
@@ -96,7 +96,7 @@ Thanks goes to these wonderful people ([emoji key](https://github.com/kentcdodds
 <!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
 | [<img src="https://avatars.githubusercontent.com/u/3869412?v=3" width="100px;"/><br /><sub>Jeroen Engels</sub>](https://github.com/jfmengels)<br />[💻](https://github.com/jfmengels/all-contributors-cli/commits?author=jfmengels "Code") [📖](https://github.com/jfmengels/all-contributors-cli/commits?author=jfmengels "Documentation") [⚠️](https://github.com/jfmengels/all-contributors-cli/commits?author=jfmengels "Tests") | [<img src="https://avatars.githubusercontent.com/u/1500684?v=3" width="100px;"/><br /><sub>Kent C. Dodds</sub>](http://kentcdodds.com/)<br />[📖](https://github.com/jfmengels/all-contributors-cli/commits?author=kentcdodds "Documentation") [💻](https://github.com/jfmengels/all-contributors-cli/commits?author=kentcdodds "Code") | [<img src="https://avatars.githubusercontent.com/u/14871650?v=3" width="100px;"/><br /><sub>João Guimarães</sub>](https://github.com/jccguimaraes)<br />[💻](https://github.com/jfmengels/all-contributors-cli/commits?author=jccguimaraes "Code") | [<img src="https://avatars.githubusercontent.com/u/1282980?v=3" width="100px;"/><br /><sub>Ben Briggs</sub>](http://beneb.info)<br />[💻](https://github.com/jfmengels/all-contributors-cli/commits?author=ben-eb "Code") | [<img src="https://avatars.githubusercontent.com/u/22768990?v=3" width="100px;"/><br /><sub>Itai Steinherz</sub>](https://github.com/itaisteinherz)<br />[📖](https://github.com/jfmengels/all-contributors-cli/commits?author=itaisteinherz "Documentation") [💻](https://github.com/jfmengels/all-contributors-cli/commits?author=itaisteinherz "Code") | [<img src="https://avatars.githubusercontent.com/u/5701162?v=3" width="100px;"/><br /><sub>Alex Jover</sub>](https://github.com/alexjoverm)<br />[💻](https://github.com/jfmengels/all-contributors-cli/commits?author=alexjoverm "Code") [📖](https://github.com/jfmengels/all-contributors-cli/commits?author=alexjoverm "Documentation") | [<img src="https://avatars3.githubusercontent.com/u/8212?v=3" width="100px;"/><br /><sub>Jerod Santo</sub>](https://jerodsanto.net)<br />[💻](https://github.com/jfmengels/all-contributors-cli/commits?author=jerodsanto "Code") |
 | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
-| [<img src="https://avatars1.githubusercontent.com/u/574871?v=3" width="100px;"/><br /><sub>Kevin Jalbert</sub>](https://github.com/kevinjalbert)<br />[💻](https://github.com/jfmengels/all-contributors-cli/commits?author=kevinjalbert "Code") | [<img src="https://avatars3.githubusercontent.com/u/5038030?v=4" width="100px;"/><br /><sub>tunnckoCore</sub>](https://i.am.charlike.online)<br />[🔧](#tool-charlike "Tools") |
+| [<img src="https://avatars1.githubusercontent.com/u/574871?v=3" width="100px;"/><br /><sub>Kevin Jalbert</sub>](https://github.com/kevinjalbert)<br />[💻](https://github.com/jfmengels/all-contributors-cli/commits?author=kevinjalbert "Code") | [<img src="https://avatars3.githubusercontent.com/u/5038030?v=4" width="100px;"/><br /><sub>tunnckoCore</sub>](https://i.am.charlike.online)<br />[🔧](#tool-charlike "Tools") | [<img src="https://avatars2.githubusercontent.com/u/304450?v=4" width="100px;"/><br /><sub>Mehdi Achour</sub>](https://machour.idk.tn/)<br />[💻](https://github.com/jfmengels/all-contributors-cli/commits?author=machour "Code") |
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 
 This project follows the [all-contributors](https://github.com/kentcdodds/all-contributors) specification.

lib/contributors/prompt.js

@@ -29,7 +29,8 @@ function getQuestions(options, username, contributions) {
     name: 'contributions',
     message: 'What are the contribution types?',
     when: !contributions,
-    choices: contributionChoices(options)
+    choices: contributionChoices(options),
+    validate: input => input.length ? true : 'Use space to select at least one contribution type.'
   }];
 }