diff -r a2342f26c9de -r b0b56e0f8c7f server/bo_client/app/models/document.js
--- a/server/bo_client/app/models/document.js	Fri Jan 15 15:27:56 2016 +0100
+++ b/server/bo_client/app/models/document.js	Fri Jan 15 15:35:00 2016 +0100
@@ -8,6 +8,8 @@
 
   title: DS.attr('string'),
 
+  language: DS.attr('string'),
+
   publishers: DS.attr({defaultValue: []}),
 
   contributors: DS.attr({defaultValue: []}),
@@ -29,4 +31,43 @@
     }
     return res;
   }),
+
+  addContributor: function(contrib_def) {
+    var contributors = this.get('contributors');
+    if(_.findIndex(contributors, function(c) { return _.isEqual(c, contrib_def);}) < 0) {
+      contributors.pushObject(contrib_def);
+    }
+    // must set dirty
+    this.set('contributors', _.clone(this.get('contributors')));
+  },
+  removeContributor: function(contrib_def) {
+    var contributors = this.get('contributors');
+    var index = _.findIndex(contributors, function(c) { return _.isEqual(c, contrib_def);});
+    if(index >= 0) {
+      contributors.removeAt(index);
+    }
+    //must set dirty
+    this.set('contributors', _.clone(this.get('contributors')));
+  },
+  saveContributor: function(contrib_def, index) {
+    var contributors = this.get('contributors');
+    if(index < 0 || index >= contributors.length) {
+      return;
+    }
+
+    var contrib_def_map = {name: contrib_def.name||"", url: contrib_def.url||"", role: contrib_def.role||""};
+    var existingContribs = _.filter(contributors, function(c, i) {
+      return (i!==index && _.isEqual({name: c.name||"", url: c.url||"", role: c.role||""}, contrib_def_map));
+    });
+    if(existingContribs.length > 0) {
+      // contributor exists, remove contributor @ index
+      contributors.removeAt(index);
+    }
+    else {
+      contributors[index] = contrib_def;
+    }
+    //must set dirty only if needed
+    this.set('contributors', _.clone(this.get('contributors')));
+  }
+
 });