Add WATCHTOWER_INCLUDE_RESTARTING env for include-restarting flag (#720)

docs/arguments.md

@@ -118,6 +118,16 @@ Environment Variable: DOCKER_API_VERSION
              Default: "1.24"
 ```
 
+## Include restarting
+Will also include created and exited containers.
+
+```
+            Argument: --include-restarting
+Environment Variable: WATCHTOWER_INCLUDE_RESTARTING
+                Type: Boolean
+             Default: false
+```
+
 ## Include stopped
 Will also include created and exited containers.
 

internal/flags/flags.go

@@ -105,6 +105,12 @@ func RegisterSystemFlags(rootCmd *cobra.Command) {
 		viper.GetBool("WATCHTOWER_RUN_ONCE"),
 		"Run once now and exit")
 
+	flags.BoolP(
+		"include-restarting",
+		"",
+		viper.GetBool("WATCHTOWER_INCLUDE_RESTARTING"),
+		"Will also include restarting containers")
+
 	flags.BoolP(
 		"include-stopped",
 		"S",