title: gitlab api Tag creation error
body: <p>Hi I am trying to create a tag to a project using the gitlab api, but it keeps saying tag name not valid. I even tried using the sample in gitlab api doc.</p>
  
  <p>Here is my attempt:</p>
  
  <pre><code>➜  /tmp  curl -X POST -d @body.json https://mygitlabserver.com/api/v3/projects/9733/repository/tags --header "Content-Type:application/json" -H "PRIVATE-TOKEN:sNW8AGtLMdSGAJiGQ-gV"
  {"message":"Tag name invalid"}% 
  
  ➜  /tmp  cat body.json 
  {
      "commit": {
          "author_email": "john@example.com",
          "author_name": "John Smith",
          "authored_date": "2012-05-28T04:42:42-07:00",
          "committed_date": "2012-05-28T04:42:42-07:00",
          "committer_email": "jack@example.com",
          "committer_name": "Jack Smith",
          "id": "2695effb5807a22ff3d138d593fd856244e155e7",
          "message": "Initial commit",
          "parents_ids": [
              "2a4b78934375d7f53875269ffd4f45fd83a84ebe"
          ]
      },
      "message": null,
      "name": "v1.0.0",
      "release": {
          "description": "Amazing release. Wow",
          "tag_name": "1.0.0"
      }
  }  
  </code></pre>