Update systems.csv: Add esel.ac (#827)

This is a Community-operated bike sharing network in Aachen.

Author: 1Maxnet1

systems.csv

@@ -302,6 +302,7 @@ DE,EDEKA Grünheide,Grünheide (Mark),nextbike_ed,https://www.nextbike.de/gruenh
 DE,Eifel e-Bike,Eifel,nextbike_eb,https://www.nextbike.de/eifel-ebike/,https://gbfs.nextbike.net/maps/gbfs/v2/nextbike_eb/gbfs.json,2.3,,,
 DE,EinfachMobil,Ortenaukreis,nextbike_eh,https://www.nextbike.de/einfachmobil/,https://gbfs.nextbike.net/maps/gbfs/v2/nextbike_eh/gbfs.json,2.3,,,
 DE,Einfach Unterwegs,Germany,einfach_unterwegs,https://www.einfach-unterwegs.eu/,https://api.mobidata-bw.de/sharing/gbfs/v3/einfach_unterwegs/gbfs,3.0,,,
+DE,esel.ac,Aachen,esel_ac,https://esel.ac/,https://di.esel.ac/gbfs/gbfs.json,2.1,,,
 DE,FaRe - das Bananologen Lastenrad,Herrenberg,herrenberg_fare,https://bananologen-herrenberg.jimdosite.com/,https://api.mobidata-bw.de/sharing/gbfs/v3/herrenberg_fare/gbfs,3.0,,,
 DE,Flinkster,Germany,flinkster_carsharing,https://www.flinkster.de/,https://api.mobidata-bw.de/sharing/gbfs/v2/flinkster_carsharing/gbfs,2.3 ; 3.0,,,
 DE,flux Bikesharing,Friedrichsdorf,nextbike_ev,https://www.nextbike.de/flux-bikesharing/,https://gbfs.nextbike.net/maps/gbfs/v2/nextbike_ev/gbfs.json,2.3,,,
@@ -1245,3 +1246,4 @@ US,Veo Wichita,"Wichita, KS",Veo Mobility,https://www.veoride.com,https://cluste
 US,WE-cycle,"Aspen, CO",we_cycle,https://www.we-cycle.org,https://aspen.publicbikesystem.net/customer/gbfs/v2/gbfs.json,1.1 ; 2.3,,,
 XK,Prishtina bike,Prishtina,nextbike_gs,https://www.prishtinabike.com/,https://gbfs.nextbike.net/maps/gbfs/v2/nextbike_gs/gbfs.json,2.3,,,
 
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