update build config, bump package version and document process

.github/CONTRIBUTING.MD

@@ -13,3 +13,29 @@ I have chosen to loosely follow the [Angular Commit Guidelines](https://github.c
 # Documentation
 
 If you'd like to help us improve our documentation, please checkout our [GitHub pages repository](https://github.com/json-api-dotnet/json-api-dotnet.github.io) where we host our documentation.
+
+# Backporting Features To Prior Releases
+
+To backport a feature that has been approved and merged into `master`:
+
+## Requester
+
+Open an issue requesting the feature you would like backported. The change will be reviewed based on: 
+
+- compatibility
+- difficulty in porting the change 
+- the added value the feature provides for users on the older versions
+- how difficult it is for users to migrate from the older version to the newer version
+
+## Maintainer
+
+- Checkout the version you want to apply the feature on top of and create a new branch to release the new version:
+  ```
+  git checkout tags/v2.5.1 -b release/2.5.2
+  ```
+- Cherrypick the merge commit: `git cherry-pick {git commit SHA}`
+- Bump the package version in the csproj
+- Make any other compatibility, documentation or tooling related changes
+- Push the branch to origin and verify the build
+- Once the build is verified, create a GitHub release, tagging the release branch
+- Open a PR back to master with any other additions

appveyor.yml

@@ -18,6 +18,7 @@ branches:
   - master
   - develop
   - unstable
+  - /release\/.+/
 
 nuget:
   disable_publish_on_pr: true
@@ -38,6 +39,7 @@ test: off
 artifacts:
 - path: .\**\artifacts\**\*.nupkg
   name: NuGet
+
 deploy:
 - provider: NuGet
   server: https://www.myget.org/F/research-institute/api/v2/package
@@ -47,17 +49,28 @@ deploy:
   symbol_server: https://www.myget.org/F/research-institute/symbols/api/v2/package
   on:
     branch: develop
+
 - provider: NuGet
   server: https://www.myget.org/F/jadnc/api/v2/package
   api_key:
     secure: 6CeYcZ4Ze+57gxfeuHzqP6ldbUkPtF6pfpVM1Gw/K2jExFrAz763gNAQ++tiacq3
   skip_symbols: false
   on:
     branch: unstable
+
 - provider: NuGet
   name: production
+  skip_symbols: false
   api_key:
     secure: /fsEOgG4EdtNd6DPmko9h3NxQwx1IGDcFreGTKd2KA56U2KEkpX/L/pCGpCIEf2s
   on:
     branch: master
     appveyor_repo_tag: true
+
+- provider: NuGet
+  skip_symbols: false
+  api_key:
+    secure: /fsEOgG4EdtNd6DPmko9h3NxQwx1IGDcFreGTKd2KA56U2KEkpX/L/pCGpCIEf2s
+  on:
+    branch: /release\/.+/
+    appveyor_repo_tag: true