Changes in repmgr are:

- Add checks to test if the directories are useful for us (basically
  the checks follow the same approach as initdb does)
- Add connection parameters
- Better use of rsync
- Some more clean up of code

Changes in repmgrd are:
- Add a parameter to allow the user specify an repmgr.conf
- Change the name of the repl_status table for repl_monitor
- Create a repl_status view that also shows lag in time
- Some more clean up of code

repmgr.sql

@@ -1,17 +1,37 @@
+drop table if exists repl_nodes;
+
+/*
+ * The table repl_nodes keeps information about all machines in
+ * a cluster
+ */
 CREATE TABLE repl_nodes (
   id 		integer	primary key,
-  cluster   text	not null,
-  conninfo	text	not null
+  cluster   text	not null,	-- Name to identify the cluster
+  conninfo	text	not null 	
 );
 
 drop table if exists repl_status;
 
-CREATE TABLE repl_status(
+/*
+ * Keeps monitor info about every node and their "position" relative 
+ * to primary
+ */
+CREATE TABLE repl_monitor(
   primary_node                   INTEGER NOT NULL,
   standby_node                   INTEGER NOT NULL,
-  last_monitor_timestamp    	 TIMESTAMP WITH TIME ZONE NOT NULL,
-  last_wal_primary_location      TEXT NOT NULL,
+  last_monitor_time		    	 TIMESTAMP WITH TIME ZONE NOT NULL,
+  last_wal_primary_location      TEXT NOT NULL,		
   last_wal_standby_location      TEXT NOT NULL,
-  replication_lag                BIGINT NOT NULL,
-  apply_lag                      BIGINT NOT NULL
+  replication_lag                BIGINT NOT NULL, 
+  apply_lag                      BIGINT NOT NULL  
 );
+
+
+/*
+ * A useful view 
+ */
+CREATE VIEW repl_status AS
+SELECT *, now() - (select max(last_monitor_time) from repl_monitor b
+                    where b.primary_node = a.primary_node
+                      and b.standby_node = a.standby_node)
+  FROM repl_monitor;