feat: implement issue and pr templates

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,33 @@
+## The Problem
+
+[] 🐛 This is a bug report.
+[] 📈 This is a feature request.
+
+<!-- Please check one of the above by placing an x in the box. -->
+
+Briefly describe the issue you are experiencing (or the feature you want to see added to OpenZeppelin). Tell us what you were trying to do and what happened instead. **Remember, this is _not_ a place to ask for help debugging code; for that, we welcome you in the [OpenZeppelin Slack Channel](https://slack.openzeppelin.org/).**
+
+## 💻 Environment
+
+First, we need to know what your environment looks like.
+
+- Which version of OpenZeppelin are you using?
+- What network are you deploying to? testrpc? Ganache? Ropsten?
+- How are you deploying your OpenZeppelin-backed contracts? truffle? Remix? Let us know!
+
+## 📝 Details
+
+Describe the problem you have been experiencing in more detail. Include as much information as you think is relevant. Keep in mind that transactions can fail for many reasons; context is key here.
+
+## 🔢 Code To Reproduce Issue [ Good To Have ]
+
+Please remember that with sample code it's easier to reproduce the bug and it's much faster to fix it.
+
+```
+insert short code snippets here
+```
+
+<!-- If your code is larger, consider linking us to a repo illustrating your issue. -->
+
+## 👍 Other Information
+<!-- List any other information that is relevant to your issue. Error logs, related issues, suggestions on how to fix, Stack Overflow links, forum links, etc. -->

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,17 @@
+<!-- 🎉 Thank you for submitting a PR! Before submitting, please review the following checklist: -->
+
+- [ ] 📘 I've reviewed the [OpenZeppelin Contributor Guidelines](/docs/CONTRIBUTING.md)
+- [ ] ✅ I've added tests where applicable to test my new functionality.
+- [ ] 📖 I've made sure that my contracts are well-documented.
+- [ ] 🎨 I've run the JavaScript linter (`npm run lint:fix`) and fixed all issues.
+
+<!-- **Does this close any open issues?** If so, list them here. -->
+
+Fixes #
+
+---
+
+# 🚀 Description
+
+<!-- Describe the changes introduced in this pull request -->
+<!-- Include any context necessary for understanding the PR's purpose. -->

CONTRIBUTING.md

@@ -80,6 +80,8 @@ git checkout -b fix/some-bug
 git checkout -b remove/some-file
 ```
 
+If your branch is planned to fix an open issue, postfix your branch name with the issue number like `fix/some-bug-#123`.
+
 We expect pull requests to be rebased to the master branch before merging:
 ```sh
 git remote add zep git@github.com:OpenZeppelin/zeppelin-solidity.git