Added issue template

Author: TwoTenPvP

.github/issue_template.md

@@ -0,0 +1,44 @@
+<!-- Please replace {Please write here} with your description if the field is applicable to the issue -->
+<!-- If it's not applicable, leave the {Please write here} tag to indicate that it does not apply -->
+
+### Issue Type
+<!-- Please place an x in the type that applies -->
+* [x] Bug
+* [ ] Enhancement / Feature
+* [ ] Question
+* [ ] Other
+
+### Description
+
+{Please write here}
+
+#### Code
+```csharp
+{Please write code here}
+```
+
+### Expected Behavior
+
+{Please write here}
+
+### Actual Behavior
+
+{Please write here}
+
+#### Stacktrace
+```
+{Please write stacktrace here}
+```
+
+### Steps to Reproduce
+
+{Please write here}
+
+### Screenshot on This Problem (if possible)
+
+{Please write here}
+
+### Your Environment
+
+- Unity Version: {Please write here}
+- MLAPI Version (Commit # or release version): {Please write here}