title: Travis: Deploy after merging pull request into master
body: <p>Let's say I have <code>release-1.0.0</code> branch, and I want to create a pull request into master for this branch. After creating pull request Travis starts checks and run build script. </p>
  
  <p>If everything is ok, github gives me a green flag and allows me to merge release branch into master. I merge release branch into master and now I want deploy to start (to npm, and to github releases). </p>
  
  <p>And I want to deploy to github releases using git tag, but when I merge pr to master I lose my tag and I get something like this: <strong>Skipping a deployment with the releases provider because this is not a tagged commit</strong>.
  Any ideas of how I can do it for my git flow?
  This is my config:</p>
  
  <pre><code>language: node_js
  node_js:
   - lts/*
  install:
  - npm ci
  - npm install -g codecov
  script:
  - npm run build 
  - ./node_modules/.bin/nyc report --reporter lcovonly -- -R spec 
  - codecov
  branches:
    only: 
      - master
  deploy:
    - provider: releases
      skip_cleanup: true
      api_key:
      secure: *****
      file: 'README.md'
      on:
        tags: true
        repo: name_of_repo
        branch: master
    - provider: npm
      email: email@email.com
      api_key:
        secure: *****
        on:
          tags: true
          repo: name_of_repo
          branch: master
  </code></pre>