Add GitHub templates

.github/CONTRIBUTING.md

@@ -0,0 +1,17 @@
+# Reporting an issue
+
+## Before reporting
+
+If you have found an issue with Mars please make sure that Mars really is the cause of the problem. To do this try to reproduce the issue with using only `@CBA_A3` and `@mars` on a newly created mission.
+
+Indicate if the issue appears on stable or development version. In case it is the development version, please also include the commit SHA-1 hash.
+
+**Please note:**
+- It's not a valid to simply remove `@mars` from the mod list to confirm that Mars is the culprit.
+- If the error happens when using a **third-party mod** contact the author of the appropriate mod and report the issue there.
+
+## Reporting the issue
+
+Head over to the [Mars GitHub issue tracker](https://github.com/marseditor/Mars/issues) and press the [new issue](https://github.com/marseditor/Mars/issues/new) button in the top right corner. Add a descriptive title and complete the issue template.
+
+A video of the issue might be helpful in resolving it faster.

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,19 @@
+**Arma 3 Version:** `x.xx` (stable / rc / dev)
+**CBA Version:** `2.x.x` (stable / dev + commit hash)
+**Mars Version:** `1.x.x` (stable / dev + commit hash)
+
+**Mods:**
+- `@CBA_A3`
+- `@mars`
+
+**Description:**
+- Add a detailed description of the error. This makes it easier for us to fix the issue.
+
+**Steps to reproduce:**
+- Add the steps needed to reproduce the issue.
+
+**Where did the issue occur?**
+- Dedicated / Self-Hosted Multiplayer / Singleplayer / Editor (Singleplayer) / Editor (Multiplayer)
+
+**RPT log file:**
+- Add a link ([gist](https://gist.github.com) or [pastebin](http://pastebin.com)) to the client and/or server RPT file. An instruction to find your RPT files can be found [here](https://community.bistudio.com/wiki/Crash_Files#Arma_3).

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,4 @@
+**When merged this pull request will:**
+- Describe what this pull request will do
+- Each change in a separate line
+- Respect the [development guidelines](http://marseditor.com/docs/development/setup/#prerequisites)