Somerville cycling is climbing the friendliness rankings. The Washington, D.C.-based League of American Cyclists has recognized Somerville this month as a Silver Bicycle-Friendly Community for its commitment to creating a bikeable community. Mayor Joseph Curtatone’s office said in a press release that the designation comes two years after the city first earned a bronze-level designation from the nonprofit organization. Somerville has installed more than 25 miles of bike lanes and “sharrows” — lanes marked to alert motorists to share the road with bicyclists — in the last three years. It also held a groundbreaking in May for the extension of the Somerville Community Path from Cedar Street to Lowell Street. Since 2011, the city has also added more than 200 new bicycle parking spots and in 2012 joined the Hubway bike-sharing system, which now has 12 docking stations in the city.