Add Restart A Sequence as a postgres til.

README.md

@@ -121,6 +121,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [List All Columns Of A Specific Type](postgres/list-all-columns-of-a-specific-type.md)
 - [List All Versions Of A Function](postgres/list-all-versions-of-a-function.md)
 - [List Database Users](postgres/list-database-users.md)
+- [Restart A Sequence](postgres/restart-a-sequence.md)
 - [Send A Command To psql](postgres/send-a-command-to-psql.md)
 - [Special Math Operators](postgres/special-math-operators.md)
 - [String Contains Another String](postgres/string-contains-another-string.md)

postgres/restart-a-sequence.md

@@ -0,0 +1,14 @@
+# Restart A Sequence
+
+In postgres, if you are truncating a table or doing some other sort of
+destructive action on a table in a development or testing environment, you
+may notice that the id sequence for the primary key just keeps plugging
+along from where it last left off. The sequence can be reset to any value
+like so:
+
+```sql
+> alter sequence my_table_id_seq restart with 1;
+ALTER SEQUENCE
+```
+
+[source](http://www.postgresql.org/docs/current/static/sql-altersequence.html)