:sparkles: added p2p relationships for events posts exhibitions

plugins/cia-post-types/includes/p2p-mappings.php

         'reciprocal' => true,
         'admin_box' => $admin_box
     ]);
+    p2p_register_connection_type([
+        'name' => 'artists_to_posts',
+        'to' => 'artist',
+        'from' => 'post',
+        'reciprocal' => true,
+        'admin_box' => $admin_box
+    ]);
 
     p2p_register_connection_type([
         'name' => 'episodes_to_exhibitions',
         'reciprocal' => true,
         'admin_box' => $admin_box
     ]);
+    p2p_register_connection_type([
+        'name' => 'episodes_to_posts',
+        'to' => 'episode',
+        'from' => 'post',
+        'reciprocal' => true,
+        'admin_box' => $admin_box
+    ]);
+
+    p2p_register_connection_type([
+        'name' => 'events_to_exhibitions',
+        'to' => 'event',
+        'from' => 'exhibition',
+        'reciprocal' => true,
+        'admin_box' => $admin_box
+    ]);
+    p2p_register_connection_type([
+        'name' => 'events_to_posts',
+        'to' => 'event',
+        'from' => 'post',
+        'reciprocal' => true,
+        'admin_box' => $admin_box
+    ]);
+    
+    p2p_register_connection_type([
+        'name' => 'exhibitions_to_posts',
+        'to' => 'exhibition',
+        'from' => 'post',
+        'reciprocal' => true,
+        'admin_box' => $admin_box
+    ]);
 }
 add_action( 'p2p_init', 'all_connection_types' );