Adding a 4-node pgbench based tutorial to the docs.

Branch
------
master

Details
-------
http://git.postgresql.org/gitweb?p=slony1-engine.git;a=commitdiff;h=a7d98dba1dd6bf1790f638fc1986ad409a26319f

Modified Files
--------------
doc/pgbench-tutorial/.gitignore                 |   2 +
doc/pgbench-tutorial/01_setup_standalone_db.sh  |  54 +++++++
doc/pgbench-tutorial/02_setup_3_node_cluster.sh | 116 +++++++++++++++
doc/pgbench-tutorial/03_add_column.sh           |  34 +++++
doc/pgbench-tutorial/04_drop_table.sh           |  29 ++++
doc/pgbench-tutorial/05_add_table.sh            |  52 +++++++
doc/pgbench-tutorial/06_add_node_4.sh           |  81 +++++++++++
doc/pgbench-tutorial/07_outage_node_2.sh        |  41 ++++++
doc/pgbench-tutorial/08_resume_node_2.sh        |  47 ++++++
doc/pgbench-tutorial/09_outage_node_1.sh        |  76 ++++++++++
doc/pgbench-tutorial/10_resume_node_1.sh        |  93 ++++++++++++
doc/pgbench-tutorial/11_fail_node_1.sh          | 129 +++++++++++++++++
doc/pgbench-tutorial/12_rebuild_node_1.sh       | 182 ++++++++++++++++++++++++
doc/pgbench-tutorial/13_drop_all.sh             |  24 ++++
doc/pgbench-tutorial/README.md                  |   9 ++
doc/pgbench-tutorial/config.sh                  |  48 +++++++
doc/pgbench-tutorial/dbsums.sh                  |  23 +++
doc/pgbench-tutorial/restart_slons.sh           |  18 +++
doc/pgbench-tutorial/slon.conf                  | 133 +++++++++++++++++
doc/pgbench-tutorial/sql/03_add_column_1.sql    |  23 +++
doc/pgbench-tutorial/start_pgbench.sh           |  29 ++++
doc/pgbench-tutorial/start_slon.sh              |  23 +++
doc/pgbench-tutorial/stop_all.sh                |   7 +
doc/pgbench-tutorial/stop_pgbench.sh            |   9 ++
doc/pgbench-tutorial/stop_slon.sh               |  14 ++
25 files changed, 1296 insertions(+)