frontend: double the connection limit on PostgreSQL server

This needs better debugging, but our connection pooling is probably
pretty complicated (each WSGI daemon process can have 15 connections to
DB, 5+10 overflow).  And we have _many_ processes nowadays, while the
default connection limit is 100 in PostgreSQL.

roles/copr/frontend/tasks/psql_setup.yml

@@ -109,6 +109,15 @@
   tags:
   - config
 
+- name: set max_connections for PostgreSQL
+  lineinfile:
+    path: /var/lib/pgsql/data/postgresql.conf
+    regexp: '^max_connections ='
+    line: 'max_connections = 200'
+  notify: restart postgresql
+  tags:
+  - config
+
 - name: install psqlrc file
   copy:
     content: |