change is_org_member to take username instead of user object
change is_org_member to take username instead of user object

project-anacapa/course-github-org-tool,UCSB-CS-Using-GitHub-In-Courses/course-github-org-tool,project-anacapa/course-github-org-tool,project-anacapa/course-github-org-tool,UCSB-CS-Using-GitHub-In-Courses/course-github-org-tool,UCSB-CS-Using-GitHub-In-Courses/course-github-org-tool,project-anacapa/course-github-org-tool