Aligned schemas with README.md

Also added add text that explains the use of the credential parameter (issue from dsccommunity#58)

DSCResources/MSFT_xSQLAOGroupEnsure/MSFT_xSQLAOGroupEnsure.schema.mof

@@ -1,19 +1,17 @@
-
 [ClassVersion("1.0.0.0"), FriendlyName("xSQLAOGroupEnsure")]
 class MSFT_xSQLAOGroupEnsure : OMI_BaseResource
 {
-    [Key, ValueMap{"Present","Absent"}, Values{"Present","Absent"}] String Ensure;
-    [Key] String AvailabilityGroupName;
-    [Write] String AvailabilityGroupNameListener;
-    [Write] String AvailabilityGroupNameIP[];
-    [Write] String AvailabilityGroupSubMask[];
-    [Write] Uint32 AvailabilityGroupPort;
-    [Write, ValueMap{"None","ReadOnly","ReadIntent"}, Values{"None","ReadOnly","ReadIntent"}] String ReadableSecondary;
-    [Write, ValueMap{"Primary","Secondary"}, Values{"Primary","Secondary"}] String AutoBackupPreference;
-    [Write] Uint32 BackupPriority;
-    [Write] Uint32 EndPointPort;
-    [Write] String SQLServer;
-    [Write] String SQLInstanceName;
-    [Required, EmbeddedInstance("MSFT_Credential"), Description("Credential to be used to Grant Permissions in SQL.")] String SetupCredential;
+    [Key, Description("Determines whether the availability group should be added or removed."), ValueMap{"Present","Absent"}, Values{"Present","Absent"}] String Ensure;
+    [Key, Description("Name for availability group.")] String AvailabilityGroupName;
+    [Write, Description("Listener name for availability group.")] String AvailabilityGroupNameListener;
+    [Write, Description("List of IP addresses associated with listener.")] String AvailabilityGroupNameIP[];
+    [Write, Description("Network subnetmask for listener.")] String AvailabilityGroupSubMask[];
+    [Write, Description("Port availability group should listen on.")] Uint32 AvailabilityGroupPort;
+    [Write, Description("Mode secondaries should operate under (None, ReadOnly, ReadIntent)."), ValueMap{"None","ReadOnly","ReadIntent"}, Values{"None","ReadOnly","ReadIntent"}] String ReadableSecondary;
+    [Write, Description("Where backups should be backed up from (Primary, Secondary)."), ValueMap{"Primary","Secondary"}, Values{"Primary","Secondary"}] String AutoBackupPreference;
+    [Write, Description("The percentage weight for backup prority (default 50).")] Uint32 BackupPriority;
+    [Write, Description("he TCP port for the SQL AG Endpoint (default 5022).")] Uint32 EndPointPort;
+    [Write, Description("The SQL Server for the database.")] String SQLServer;
+    [Write, Description("The SQL instance for the database.")] String SQLInstanceName;
+    [Required, EmbeddedInstance("MSFT_Credential"), Description("Credential to be used to Grant Permissions on SQL Server, set this to $null to use Windows Authentication.")] String SetupCredential;
 };
-

DSCResources/MSFT_xSQLAlias/MSFT_xSQLAlias.schema.mof

@@ -6,5 +6,5 @@ class MSFT_xSQLAlias : OMI_BaseResource
     [Key, Description("The SQL Server you are aliasing (the real SQL Server name).")] String ServerName;
     [Write, Description("The TCP port SQL is listening on.")] Sint32 TCPPort;
     [Read, Description("Named Pipes name from the Get-TargetResource method.")] String PipeName;
-    [Write, Description("Determines if Alias is to be Present or Absent."), ValueMap{"Present","Absent"}, Values{"Present","Absent"}] String Ensure;
+    [Write, Description("Determines whether the alias should be added or removed."), ValueMap{"Present","Absent"}, Values{"Present","Absent"}] String Ensure;
 };

README.md

@@ -233,19 +233,19 @@ Please check out common DSC Resources [contributing guidelines](https://github.c
 * **SQLInstance**: The SQL instance for the database 
 
 ###xSQLAOGroupEnsure
-* **Ensure**: (key) An enumerated value that describes if Availability Group is to be present or absent.
-* **AvailabilityGroupName** (key) Name for availability group
-* **AvailabilityGroupNameListener** Listener name for availability group
-* **AvailabilityGroupNameIP** List of IP addresses associated with listener
-* **AvailabilityGroupSubMask** Network subnetmask for listener
-* **AvailabilityGroupPort** Port availability group should listen on
-* **ReadableSecondary** Mode secondaries should operate under (None, ReadOnly, ReadIntent)
-* **AutoBackupPreference** Where backups should be backed up from (Primary,Secondary)
-* **BackupPriority** The percentage weight for backup prority (default 50)
-* **EndPointPort** The TCP port for the SQL AG Endpoint (default 5022)
-* **SQLServer**: The SQL Server for the database
-* **SQLInstance**: The SQL instance for the database
-* **SetupCredential**: (Required) Credential to be used to Grant Permissions on SQL Server
+* **Ensure**: (Key) Determines whether the availability group should be added or removed.
+* **AvailabilityGroupName** (Key) Name for availability group.
+* **AvailabilityGroupNameListener** Listener name for availability group.
+* **AvailabilityGroupNameIP** List of IP addresses associated with listener.
+* **AvailabilityGroupSubMask** Network subnetmask for listener.
+* **AvailabilityGroupPort** Port availability group should listen on.
+* **ReadableSecondary** Mode secondaries should operate under (None, ReadOnly, ReadIntent).
+* **AutoBackupPreference** Where backups should be backed up from (Primary, Secondary).
+* **BackupPriority** The percentage weight for backup prority (default 50).
+* **EndPointPort** The TCP port for the SQL AG Endpoint (default 5022).
+* **SQLServer**: The SQL Server for the database.
+* **SQLInstance**: The SQL instance for the database.
+* **SetupCredential**: (Required) Credential to be used to Grant Permissions on SQL Server, set this to $null to use Windows Authentication. 
 
 ###xSQLServerAOJoin
 * **Ensure**: (key) An enumerated value that describes if Replica is to be present or absent from availability group
@@ -330,7 +330,7 @@ Please check out common DSC Resources [contributing guidelines](https://github.c
 * **Variable**: Creates a sqlcmd scripting variable for use in the sqlcmd script, and sets a value for the variable.
 
 ### xSqlAlias
- * **Ensure**: Determines if Alias is to be Present or Absent.
+ * **Ensure**: Determines whether the alias should be added or removed.
  * **Name**: (Key) The name of Alias (e.g. svr01\inst01).
  * **ServerName**: (Key) The SQL Server you are aliasing (the real SQL Server name).
  * **Protocol**: Protocol to use when connecting. Valid values are TCP or NP. NP is Named Pipes.