diff --git a/app/models/project_group.rb b/app/models/project_group.rb
index a3be229..05a4c1e 100644
--- a/app/models/project_group.rb
+++ b/app/models/project_group.rb
@@ -1,44 +1,66 @@
 class ProjectGroup < ActiveRecord::Base
 
-  	#associations between tables
-  	belongs_to :project
-  	belongs_to :user
-  
-  	attr_accessible :project_creator, :project_editor, :project_administrator, :project_id, :user_id, :email, :access_level, :as => [:default, :admin]
-  
-  	def email
-  		unless user.nil? 
-  			return user.email
-  		end
-  	end
-  
-  	def email=(new_email)
-  		unless User.find_by_email(email).nil? then
-			user = User.find_by_email(email)
+	#associations between tables
+	belongs_to :project
+	belongs_to :user
+
+	attr_accessible :project_creator, :project_editor, :project_administrator, :project_id, :user_id, :email, :access_level, :as => [:default, :admin]
+
+  ##
+  # returns the user's email unless it is nil
+  #
+  # @return [Boolean, String] false if no email exists, the email otherwise
+	def email
+		unless user.nil? 
+			return user.email
 		end
-  	end
-  
-  	def access_level
-  		if project_administrator then
-  			return 3
-  		elsif project_editor then
-  			return 2
-  		else
-  			return 1
-  		end
-  	end
-  	
-  	def access_level=(new_access_level)
-  		new_access_level = new_access_level.to_i
-  		if new_access_level >= 3 then
-  			project_administrator = true
-  		else
-  			project_administrator = false
-  		end
-  		if new_access_level >= 2 then
-  			project_editor = true
-  		else
-  			project_editor = false
-  		end
-  	end
+	end
+
+  ##
+  # define a new user for the project group by email
+  #
+  # @param new_email [String] the email of the new user for the project group
+  # @return [User] the new user
+	def email=(new_email)
+		unless User.find_by(email: email).nil? then
+		user = User.find_by(email: email)
+    end
+	end
+
+  ##
+  # return the access level for the current project group
+  # 3 if the user is an administrator
+  # 2 if the user is an editor
+  # 1 if the user can only read
+  #
+  # @return [Integer]
+	def access_level
+		if project_administrator then
+			return 3
+		elsif project_editor then
+			return 2
+		else
+			return 1
+		end
+	end
+
+  ##
+  # define a new access level for the current project group
+  # if >=3, the user is a project administrator
+  # if >=2, the user is an editor
+  #
+  # @param new_access_level [Integer] the access level to give the user
+	def access_level=(new_access_level)
+		new_access_level = new_access_level.to_i
+		if new_access_level >= 3 then
+			project_administrator = true
+		else
+			project_administrator = false
+		end
+		if new_access_level >= 2 then
+			project_editor = true
+		else
+			project_editor = false
+		end
+	end
 end