Added documentation for rule configuration

Author: Bart Koelman

README.md

@@ -30,6 +30,9 @@ The latest version requires [Visual Studio 2017 with Update 5](https://www.visua
 
 * Optional: [Reference CSharpGuidelines.Layer.DotSettings in your existing Resharper preferences](/docs/Resharper%20Settings.md)
 
+## Rule configuration
+The behavior of a few rules can optionally be customized using a configuration file. See [documentation](docs/Configuration.md) for details.
+
 ## Suppressing rules
 Rule warnings can be suppressed at various scopes, ranging from per line to at the project or solution level.
 

docs/Configuration.md

@@ -0,0 +1,28 @@
+# Rule configuration
+
+The behavior of rules can be customized by adding a file named `CSharpGuidelinesAnalyzer.config` to your C# project with the following structure:
+
+```xml
+<?xml version="1.0" encoding="utf-8"?>
+<cSharpGuidelinesAnalyzerSettings>
+  <setting rule="AV1500" name="MaxStatementCount" value="12" />
+  <setting rule="AV1561" name="MaxParameterCount" value="5" />
+</cSharpGuidelinesAnalyzerSettings>
+```
+
+The next step is to change the Build Action (Properties window) of this file to **AdditionalFiles** (or **C# analyzer additional file**, depending on project type). This should result in the following line added to your project file:
+
+```xml
+<AdditionalFiles Include="CSharpGuidelinesAnalyzer.config" />
+```
+
+For a complete list of the available rules and their configuration settings, see [Overview](/docs/Overview.md).
+
+## Multiple projects
+
+If your solution consists of multiple projects, you can share the configuration by moving `CSharpGuidelinesAnalyzer.config` to the solution folder and updating your project files to use a relative link:
+```xml
+<AdditionalFiles Include="..\CSharpGuidelinesAnalyzer.config">
+  <Link>CSharpGuidelinesAnalyzer.config</Link>
+</AdditionalFiles>
+```

docs/Overview.md

@@ -49,6 +49,8 @@ This analyzer reports when a method return type is `IEnumerable` or `IEnumerable
 ### [AV1500](https://github.com/dennisdoomen/CSharpGuidelines/blob/1a90b74c95225a0f7e4d0e7a341fd027e17c2320/_pages/1500_MaintainabilityGuidelines.md#av1500): Methods should not exceed 7 statements ![](/images/warn.png "severity: warning")
 This analyzer reports when a method body (such as a method, property getter or local function) contains more than 7 statements.
 
+**Note:** This rule can be customized using a [configuration file](/docs/Configuration.md) by setting **MaxStatementCount** to a value in range 0-255.
+
 ### [AV1502](https://github.com/dennisdoomen/CSharpGuidelines/blob/1a90b74c95225a0f7e4d0e7a341fd027e17c2320/_pages/1500_MaintainabilityGuidelines.md#av1502): Avoid conditions with double negatives ![](/images/warn.png "severity: warning")
 This analyzer reports when the logical not operator is applied on an argument that has the word "No" or "Not" in its name.
 
@@ -100,6 +102,8 @@ This analyzer reports when a method, constructor, local function, indexer or del
 - declares a tuple parameter
 - returns a tuple with more than 2 elements.
 
+**Note:** This rule can be customized using a [configuration file](/docs/Configuration.md) by setting **MaxParameterCount** to a value in range 0-255.
+
 ### [AV1562](https://github.com/dennisdoomen/CSharpGuidelines/blob/1a90b74c95225a0f7e4d0e7a341fd027e17c2320/_pages/1500_MaintainabilityGuidelines.md#av1562): Don't use ref or out parameters ![](/images/warn.png "severity: warning")
 This analyzer reports when:
 - a parameter is declared as `ref`