add issue templates

.github/ISSUE_TEMPLATE/bug-report.md

+---
+name: "\U0001F41B Bug Report"
+about: Submit a bug report to help us improve PyTorch Transformers
+---
+
+## 🐛 Bug
+
+<!-- A clear and concise description of what the bug is. -->
+
+## To Reproduce
+
+Steps to reproduce the behavior:
+
+1.
+2.
+3.
+
+<!-- If you have a code sample, error messages, stack traces, please provide it here as well. -->
+
+## Expected behavior
+
+<!-- A clear and concise description of what you expected to happen. -->
+
+## Environment
+
+* OS:
+* Python version:
+* PyTorch version:
+* PyTorch Transformers version (or branch):
+* Using GPU ?
+* Distributed of parallel setup ?
+* Any other relevant information:
+
+## Additional context
+
+<!-- Add any other context about the problem here. -->
\ No newline at end of file

.github/ISSUE_TEMPLATE/feature-request.md

+---
+name: "\U0001F680 Feature Request"
+about: Submit a proposal/request for a new PyTorch Transformers feature
+---
+
+## 🚀 Feature
+
+<!-- A clear and concise description of the feature proposal. Please provide a link to the paper and code in case they exist. -->
+
+## Motivation
+
+<!-- Please outline the motivation for the proposal. Is your feature request related to a problem? e.g., I'm always frustrated when [...]. If this is related to another GitHub issue, please link here too. -->
+
+## Additional context
+
+<!-- Add any other context or screenshots about the feature request here. -->
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.github/ISSUE_TEMPLATE/migration.md

+---
+name: "\U0001F4DA Migration from PyTorch-pretrained-Bert"
+about: Report a problem when migrating from PyTorch-pretrained-Bert to PyTorch-Transformers
+---
+
+## 📚 Migration
+
+<!-- Give at least the following information -->
+
+Model I am using (Bert, XLNet....):
+
+The problem arise when using:
+* [ ] the official example scripts
+* [ ] my own modified scripts
+
+The tasks I am working on is:
+* [ ] an official GLUE/SQUaD task: (give the name)
+* [ ] my own task or dataset: (give details)
+
+Language I am using the model on (English, Chinese....):
+
+Details of the issue:
+
+<!-- A clear and concise description of the migration issue. If you have code snippets, please provide it here as well. -->
+
+## Environment
+
+* OS:
+* Python version:
+* PyTorch version:
+* PyTorch Transformers version (or branch):
+* Using GPU ?
+* Distributed of parallel setup ?
+* Any other relevant information:
+
+## Checklist
+
+- [ ] I have read the migration guide in the readme.
+- [ ] I checked if a related official extension example runs on my machine.
+
+## Additional context
+
+<!-- Add any other context about the problem here. -->
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.github/ISSUE_TEMPLATE/question-help.md

+---
+name: "❓Questions & Help"
+about: Start a general discussion related to PyTorch Transformers
+---
+
+## ❓ Questions & Help
+
+<!-- A clear and concise description of the question. -->
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