add CHANGELOG.md (#184)

* add CHANGELOG.md

* update PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -4,17 +4,31 @@ v    Before smashing the submit button please review the checkboxes.
 v    If a checkbox is n/a - please still include it but + a little note why
 ☺ > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >  -->
 
-- Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ethermint/blob/master/CONTRIBUTING.md#pr-targeting))
+Closes: #XXX
 
-- [ ] Linked to github-issue with discussion and accepted design OR link to spec that describes this work.
-- [ ] Wrote tests
-- [ ] Updated relevant documentation (`docs/`)
-- [ ] Added entries in `PENDING.md` with issue # 
-- [ ] rereviewed `Files changed` in the github PR explorer
+## Description
+
+<!-- Add a description of the changes that this PR introduces and the files that
+are the most critical to review.
+-->
 
 ______
 
-For Admin Use:
-- Added appropriate labels to PR (ex. wip, ready-for-review, docs)
-- Reviewers Assigned
-- Squashed all commits, uses message "Merge pull request #XYZ: [title]"
+For contributor use:
+
+- [ ] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
+- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
+- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
+- [ ] Wrote unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
+- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
+- [ ] Added  relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
+- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
+- [ ] Re-reviewed `Files changed` in the Github PR explorer
+
+______
+
+For admin use:
+
+- [ ] Added appropriate labels to PR (ex. `WIP`, `R4R`, `docs`, etc)
+- [ ] Reviewers assigned
+- [ ] Squashed all commits, uses message "Merge pull request #XYZ: [title]" ([coding standards](https://github.com/tendermint/coding/blob/master/README.md#merging-a-pr))

CHANGELOG.md

@@ -0,0 +1,38 @@
+<!--
+Guiding Principles:
+
+Changelogs are for humans, not machines.
+There should be an entry for every single version.
+The same types of changes should be grouped.
+Versions and sections should be linkable.
+The latest version comes first.
+The release date of each version is displayed.
+Mention whether you follow Semantic Versioning.
+
+Usage:
+
+Change log entries are to be added to the Unreleased section under the
+appropriate stanza (see below). Each entry should ideally include a tag and
+the Github issue reference in the following format:
+
+* (<tag>) \#<issue-number> message
+
+The issue numbers will later be link-ified during the release process so you do
+not have to worry about including a link manually, but you can if you wish.
+
+Types of changes (Stanzas):
+
+"Features" for new features.
+"Improvements" for changes in existing functionality.
+"Deprecated" for soon-to-be removed features.
+"Bug Fixes" for any bug fixes.
+"Client Breaking" for breaking CLI commands and REST routes used by end-users.
+"API Breaking" for breaking exported APIs used by developers building on SDK.
+"State Machine Breaking" for any changes that result in a different AppState given same genesisState and txList.
+
+Ref: https://keepachangelog.com/en/1.0.0/
+-->
+
+# Changelog
+
+## [Unreleased]