Add Github release feature

Author: wanseob

Diff for: .travis.yml

@@ -6,7 +6,17 @@ node_js:
 after_success:
   - CURRENT_VERSION=$(node -p "require('./package.json').version")
   - LATEST=$(npm view $(node -p "require('./package.json').name") dist-tags.latest)
-  - STABLE=$(npm view $(node -p "require('./package.json').name") dist-tags.latest)
+  - STABLE=$(npm view $(node -p "require('./package.json').name") dist-tags.stable)
+
+before_deploy:
+  - if [ "$LATEST" != "CURRENT_VERSION" ] && [ "$TRAVIS_BRANCH" = "develop" ]; then
+      echo "on develop branch";
+      export TRAVIS_TAG=v$(CURRENT_VERSION);
+    fi;
+  - if [ "$STABLE" != "CURRENT_VERSION" ] && [ "$TRAVIS_BRANCH" = "master" ]; then
+      echo "on master branch";
+      export TRAVIS_TAG=v$(CURRENT_VERSION)-stable;
+    fi;
 
 deploy:
   - provider: npm
@@ -27,3 +37,18 @@ deploy:
       condition: $LATEST != CURRENT_VERSION
       branch: develop
       repo: commitground/commitground-js
+  - provider: releases
+    api_key:
+      secure: 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
+    on:
+      tags: true
+      repo: commitground/commitground-js
+      branch: master
+  - provider: releases
+    prerelease: true
+    api_key:
+      secure: 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
+    on:
+      tags: true
+      repo: commitground/commitground-js
+      branch: develop