Somerville alderman Bill Roche resigned last week and accepted an interim part-time job as the city’s personnel director. Roche, who has served on the board for 17 years representing Ward 1, said increasing family obligations were making it difficult to fully satisfy his duties as an alderman. “I still thoroughly enjoy the job. However I found that due to conflicting personal, social, and family priorities I am no longer able to dedicate the time required to effectively and successfully do the job,” he said during an aldermen’s meeting last Thursday. Somerville Mayor Joseph Curtatone announced Roche’s appointment as personnel director shortly after his resignation. Roche will be paid hourly as he works around his full-time job as safety and compliance manager for NStar. At Roche’s request, the Board of Aldermen appointed School Committee member Maureen Bastardi as his replacement.