Add ISSUE_TEMPLATE for GitHub

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,26 @@
+<!--
+Please remember that issues here should be related to the library itself and NOT your code.
+
+Python 2 is NOT supported. Make sure you're using the latest version of Telethon before reporting:
+    pip install telethon --upgrade
+
+Some questions are okay, but make sure you've investigated enough on your own before or you will end up on the Wall of Shame:
+    https://github.com/LonamiWebs/Telethon/wiki/Wall-of-Shame.
+-->
+
+### What went wrong
+Describe what happened or what the error you have is.
+
+```
+// paste the crash log here if any, or remove these 3 lines if nothing happens
+```
+
+### What I've done
+Either a code example of what you were trying to do, or steps to reproduce, or methods you have tried invoking.
+
+```python
+# Add your Python code here, or remove these 3 lines
+```
+
+### More information
+If you think other information can be relevant (e.g. operative system or other variables), add it here. You may remove this block otherwise.