Add yarn/npm install to readme on yarn condition

__tests__/readme.js

@@ -182,3 +182,29 @@ describe('node:readme --no-coveralls and --generate-into', () => {
     assert.noFileContent('other/README.md', 'coveralls');
   });
 });
+
+describe('node:readme --yarn', () => {
+  beforeEach(() => {
+    return helpers
+      .run(require.resolve('../generators/readme'))
+      .withOptions({
+        name: 'my-project',
+        description: 'a cool project',
+        githubAccount: 'yeoman',
+        authorName: 'Yeoman',
+        authorUrl: 'http://yeoman.io',
+        yarn: true,
+        coveralls: false
+      })
+      .on('ready', gen => {
+        gen.fs.writeJSON(gen.destinationPath('package.json'), {
+          license: 'MIT'
+        });
+      });
+  });
+
+  it('creates and fills contents in README.md', () => {
+    assert.file('README.md');
+    assert.fileContent('README.md', '$ yarn add my-project');
+  });
+});

generators/readme/index.js

@@ -84,6 +84,7 @@ module.exports = class extends Generator {
         },
         license: pkg.license,
         includeCoveralls: this.options.coveralls,
+        yarn: this.options.yarn,
         content: this.options.content
       }
     );

generators/readme/templates/README.md

@@ -7,7 +7,11 @@ if (includeCoveralls) { %> [![Coverage percentage][coveralls-image]][coveralls-u
 ## Installation
 
 ```sh
+<% if (yarn) { -%>
+$ yarn add <%= projectName %>
+<% } else { -%>
 $ npm install --save <%= projectName %>
+<% } -%>
 ```
 
 ## Usage