Fix conflicting bootstrap in index and add select2 in non-cdn resource
Fix conflicting bootstrap in index and add select2 in non-cdn resource

hackmdio/hackmd,PeterDaveHello/hackmd,jccrofty30/hackmd,Rwing/hackmd,aswathyjacob8/newtest,jccrofty30/hackmd,ironhack/hackmd,aswathyjacob8/newtest,Yukaii/hackmd,ironhack/hackmd,jccrofty30/hackmd,PeterDaveHello/hackmd,Rwing/hackmd,Rwing/hackmd,Yukaii/hackmd,aswathyjacob8/newtest,Yukaii/hackmd,jackycute/HackMD,jackycute/HackMD,jackycute/HackMD,hackmdio/hackmd,hackmdio/hackmd,ironhack/hackmd,PeterDaveHello/hackmd