Add links to contribution guidelines

.github/ISSUE_TEMPLATE/bug_report.md

@@ -6,6 +6,7 @@ labels: ''
 assignees: ''
 
 ---
+<!-- Please have a look at our [Contributing Guidelines](https://github.com/janeczku/calibre-web/CONTRIBUTING.md) -->
 
 **Describe the bug/problem**
 A clear and concise description of what the bug is. If you are asking for support, please check our [Wiki](https://github.com/janeczku/calibre-web/wiki) if your question is already answered there.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -7,6 +7,8 @@ assignees: ''
 
 ---
 
+<!-- Please have a look at our [Contributing Guidelines](https://github.com/janeczku/calibre-web/CONTRIBUTING.md) -->
+
 **Is your feature request related to a problem? Please describe.**
 A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
 

README.md

@@ -83,3 +83,7 @@ Pre-built Docker images are available in these Docker Hub repositories:
 # Wiki
 
 For further information, How To's and FAQ please check the [Wiki](https://github.com/janeczku/calibre-web/wiki)
+
+# Contributing to Calibre-Web
+
+Please have a look at our [Contributing Guidelines](https://github.com/janeczku/calibre-web/CONTRIBUTING.md)