Merge pull request #238 from yousraHazem/development

Merge sprint 1 work into master
fixed_empty_message_problem
trying_to_fix_display
fixing conflicts to merge it
#260 fixing code according to comments
fixed recepient exist
#260 fixing documentation errors
#260 refixing code errors
Merge pull request #330 from yousraHazem/C4_S18_view_members_of_group

C4_S18_view_members_of_group
Fixed destroy group bug, fixed show view, added error reporting for groups form and added documentation for changes. #279
Finished the first three tasks of the story #279
AJAX for this story checkbox is partially done #275
Modified the code logic in html and controller, #275
fixed bug in view friend list
fixed bug in send_friend_request branch
fixed bug in view pending friends branch
added friend list view
added friendship controller
Update groups_controller.rb

Updated the documentation in groups_controller.rb related to issue #279
Update groups_controller.rb

Updated documentation in groups controller