Contribution guide in the docs

Author: phortx

docs/.vuepress/config.yml

@@ -33,3 +33,4 @@ themeConfig:
     - /guide/meta-fields/
     - /guide/testing/
     - /guide/faq/
+    - /guide/contribution/

docs/guide/contribution/README.md

@@ -0,0 +1,55 @@
+# Contribution
+
+[[toc]]
+
+To test this plugin in your existing project, you can use `yarn link` functionality. Run `yarn link`
+in your local plugin-graphql directory and run `yarn link @vuex-orm/plugin-graphql` in your project dir.
+
+Remember to run `yarn build` in your plugin-graphql directory and then again `yarn link` in your project after you have
+made changes to the plugin code. You probably have also to restart your webpack server.
+
+
+```bash
+$ yarn run build
+```
+
+Compile files and generate bundles in dist directory.
+
+```bash
+$ yarn run lint
+```
+
+Lint files using a rule of Standard JS.
+
+```bash
+$ yarn run test
+```
+
+Run the test using Mocha Webpack.
+
+```bash
+$ yarn run coverage
+```
+
+Generate test coverage in coverage directory.
+
+
+```bash
+yarn docs:build
+```
+
+Builds the documentation.
+
+
+```bash
+yarn docs:dev
+```
+
+Spawns a server for the documentation.
+
+
+```bash
+yarn docs:depoy
+```
+
+Deploys the documentation.